Abstract: This paper first introduces the code and phase models used in precise point positioning(PPP) method,then the principle and simple procedure of PPP processing algorithm are introduced,and the main error sources of PPP method are presented.A lot of attentions are paid to the methods of quality control for PPP method.What's more,the estimation and interpolation of satellite clock errors,the consistence of data and solution and the accuracy that PPP method can attain are discussed.Last,an example of PPP is processed and the corresponding results are compared with the results obtained by using GPS double difference observations.The results show that the accuracy of PPP can attain cm-precision and is approximately equal to that of double difference with long baselines(>1 000km).