Research conclusions: It is recommended that limited gradient is 9%0 and assisting gradient is 18%0. According to all kinds of analysis, the proposal with limited gradient of 9%o and assisting gradient of 18%0 is adaptable to landform better and save investment of project, satisfies the speed and traction mass requirements of freight train and the transport requirement due to few increase of running time, is more reasonable when the total construction period is the same and balanced in proportion of human power and funds inputted for the whole line and has not appear the situation which is abort of human power and funds and has stronger anti-risk ability for sudden accident as the double spur grade is adopted in tunnels in the soluble rock stratum. Therefore it has been determined that the proposal with limited gradient of 9%0 and assisting gradient of 18%0 is adopted for this route.