Abstract: n order to improve the accuracy of the prediction of satellite's orbit, the calculation methods of atmospheric drag perturbation are studied. On the basis of the principle of atmospheric drag perturbation this paper describes two methods: numerical method and combining both of analytical and numerical method. The error δp of the satellite's position in orbit due to various level (F10.7 of 150, 200 and 250) of solar activity and the model's error of 10%- 20% are analyzed for three kinds of upper atmosphere models: CIRA-1986, CIRA-1972 and DTM. The results show that: ① The effect of the solar activity level on the error δp is obvious. The error δp increases fast with F10.7 in case of given atmosephere model error. ② The error δp increases proportionally as the difference between the model and the reality increases. ③ The error a, due to the variety of atmosphere model is not noticeable in general, but when F10.7 is greater than 200 the difference between DTM model and CIRA model is very noticeable.