Abstract:   To Combining with the Nanning BeiDou ground-based augmengtation system demonstration project actual production pyactice,the test of time availability, RTK positioning accuracy(including the effect after encryption station) and spatial availability had been done.The results show that the Nanning BeiDou ground-based augmengtation system meets cenmetre order for RTK positioning in all-day and 95％ coverage of Nanning area.Compared with single GPS and single BDS,the combination of GPS+BDS in reliability.time availability fo RTK positioning under the hidden environment is improved obviously.