Abstract: Usually the high precision GPS network lasts two or more years.In this period the GPS observation epoch,GPS satellite situation,GPS receivers,observing environment,the reference frame of ephemeris and even the surveying standard have changed,which will cause complex systematical errors.In this paper,all kinds of systematical errors of stochastic model in adjustment are discussed in details.And the relative adjustment model to estimate the systematical error parameters is established.In practice,the whole network is usually divided into some sub-nets,and each sub-net must have some systematical errors.With the different systematical errors,the theoretical estimation model,relative arithmetic and the statistical proof-test methods of systematical error parameters are also discussed in details.