Abstract: Through the analysis of the mechanism of multi-path error, this paper presents some measures on eliminating multi-path error in measurement.The character of multi-path error at one station under the same condition is mainly studied to infer the temporal correlation of the error.Multipath errors of the correlation would be delayed four minutes a day.Discuss the multi-path error and the relationship with temperature and pressure.This character is helpful for the further research of multi-path error elimination.