Abstract: The influence of main different parameters on spaceship's trajectory and the destination of orbit was mainly analyzed when the manned spacecraft flied in extra-atmosphere,which is called sensitivity.In the process of analysis,firstly,the mathematical models of extra-atmospheric flight were established,furthermore,the datum orbit was gotten according to a number of numerical simulation,the initial parameter value of orbit's starting point(IPVOSP)(path angle,yawangle and the velocity of flight) were varied,which is based on the datum orbit.The changing condition and the error of destination of orbit(EDO) were analyzed.Finally,the results were obtained according to the relation between IPVOSP and EDO,which will offer effective reference basis to the design of orbit in engineering.