The paper analyze and deduced the error of QUEST algorithm and the uniform relationship with traditional TRAID method for SINS alignment in inertial frame in detail. MonteCarlo simulations analyzed the precision of observation scheme with gravity vectors and gravity integration vectors and the precision of different AD algorithms comparatively.Theory analysis and simulation test show that the QUEST algorithm can achieve the higher precision compared with TRAID under equivalent precision observation condition, and the variance of calculation drops to one sixth of the origin,which can give the theory foundation of algorithm application on rocking base alignment.