Abstract: In this paper, both tracking errorsdue to multipath effects considered autocorrelation sidelobe in GPS and the effect of different early-late spacing are studied. Based on noncoherent DLL and arctan carrier PLL, the curves of tracking errors in general forms are given after a series of computing and simulation.It is shown that tracking errors are different in different regions; autocorrelation sidelobe affects the code phase and carrier phase tracking errors of the longer time reative multipath delay; a smaller early-late spacing can reduce the tracking errors both of code phase and of carrier phase.