I am a new sim flyer. During take off rudder steering is normal. After landing during taxi the airplane aileron flip radically and the plane goes into an uncontrollable taxi. Please how to get rid of the issue. Thanks

I'm not sure whether I understand your problem correctly: Do you try to use the ailerons to steer or the rudder?

If you use the ailerons, that won't work, it's way too unprecise. If you use the rudder (which is actually ineffective at taxi speeds as well, but in FSX it'S usually linked to the steerable wheel for ground movement), you should not have any problems in most planes.

Another thought is that you're not useing auto brakes, but brake manually and make rudder inputs during braking: This will engage the differential brakes, which will make many planes hard to control, particularly those that land at high speeds like fighters.

Also, keep taxi speeds at or below 25 knots. If you are going through a tight 90 degree turn keep speeds at or below 10 knots

This happens at very low taxi speed. In many cases I taxi hands off the ailerons and it still happens. If I use the differential brake it will cause loss of steering control also.

Which aircraft is doing this and what control devices are you using?

Flying the 172, Saitek yoke, Saitek rudder pedals. Thanks

On the ground, your ailerons will have no effect at all.  Make sure you are not going particularly fast when attempting to steer your aircraft.  Turns need to be made at fairly slow speeds. 

Check to make sure your rudder pedals are not assigned to alierons in the FSX axis menu.

Could it be some calibration issue? The "sudden flip of the ailerons" sounds a bit like that to me, especially since you say that you taxi with the hands off the ailerons.