Philosophy is looking for reason but why philosophers have different prospective about life and....if there were be a rational reason for something all of them must accept it. Am I wrong?
If philosophy is a rational inquiry, why do philosophers disagree ? That seems to be what you are asking. A proper first step is to decide what we mean by disagreement in this context.
▻ Nature of disagreement
Philosophers can disagree about many things but to give focus to the question let's assume that they disagree over propositions. Such disagreement can take at least three forms : (1) I believe that p, and you believe that not-p; (2) I believe that p and you do not believe that p; (3) I believe that p and you believe that p but we attach different probabilities (I am certain that p but you regard p as merely highly probable).
How can such disagreements rationally arise ? I think they have two bases, one cognitive and the other evidential.
▻ Cognitive differences
As rational equals philosophers can still disagree if they are cognitively differentiated. I can be as rational as you but less intelligent. You can have a stronger and more accurate memory than I have. You may be able to express your meaning more clearly than I can, and I may be slower at recognising that meaning. We may also fail to realise that we are using the terms but with different meanings. Such factors are seedbeds for disagreement.
▻ Evidential differences
What is it rational to believe depends (not only but to some extent) on the evidence available. It was rational for the ancients to believe the geocentric theory that the sun rotated around the earth because that's what the incomplete and defective evidence available at least to most of them indicated. We have different evidence and a different belief about the geocentric theory. But our rational belief is equally indexed to evidence. It is perfectly possible for equally rational philosophers to have access to different levels of information. With differences of information, what it is rational for one philosopher to believe may not be what it is rational for another to believe.
In light of these considerations, disagreements between equally rational philosophers are perfectly possible, unsurprising, and even to be expected.
Simply put, the position of philosopher as an observer has already different. Pulling it down from top to downside, from social, down to particle, where those are having different position relevant to different viewpoint, therefore those must produce different sightseeing however it is.
You might say that there were two with the same quality of understanding but actually not identical at all. Because when you try to understand things from different people, you may consider any possible different aspect from the speaker.
We all know the children of the same parents need not necessarily be of the same opinion. Even twins differ in their tastes and abilities. Since the philosophers you meant are the product of different areas, times, etc, their life experiences would be different and so their perspective about life would also have difference.
We, the decision makers, should also be included in the above category. Also, since it is about life we cannot quantify them and decide which one is absolutely rational. This is happening in the case of most philosophers.
But in the case of men who reached the topmost level, since they know each other, they have explained the same thing in different ways. We will also be able to know this when we reach that level.
Just as you speculate I would say you are wrong. Philosophers generally do not accept the results of philosophical analysis and so the facts have almost no normalising influence, leaving philosophers to promote a vast range of different views.
This is true only for Russell's 'rational' tradition and it would be a mistake to assume this free-for-all of opinion is forced on philosophers. It is a consequence of ignoring metaphysics.
There are rational reasons for accepting the results of metaphysics but surprisingly this does not ensure that philosophers accept them. Rationality is a more rare approach to philosophy than you might imagine.