Abstract: The goal in designing a GPS code pseudorange smoothing algorithm is to smooth the random noise of the code pseudorange by means of the carrier observables and to improve the positioning accuracy when the requirement for real-time kinematic point determination is satisfied.The performance of smoothing algorithm is dominated by three factors of the receiver performance,the choice of weight factor,and the recursive time.Theoretic discussion of evaluation of the smoothing algorithm is made in this paper.And a smoothing algorithm with optimal weight factor is given here,which has the fastest noise reduction performance.