GNSS receiver usually use the match filter and FFT to get the code phase and carrier frequency.However,it is hard to get thecode phase and carrier frequency under high dynamic condition,And the match filter and FFT will occupy huge hardware resource.The INS (Inertial Navigation System) can assist the GNSS receiver to get the carrier frequency.It can also improve the calculate effi-ciency.But the carrier frequency acquisition error can also affect the carrier frequency lock.It may affect the GNSS signal track.To solve this problem,this paper proposed a fast acquisition algorithm in GNSS/INS ultratightlyintegrated navigation system based on steady statejudgment.This algorithm can effectively lock the carrier frequency under high dynamic condition.And this algorithm can also judge the acquisition condition to control the switch between acquisition and tracking to improve higher carrier frequency tracking accurate.