So this paper starts with from the investigation of new students math basic condition,people can know about the basic condition of new students,and seek the joint-point,in order to offer some ways and thoughts for later teaching.

The dedicated passenger railway can t have its own network shortly which cause lots of cross-line trains s existence, and the problem of choosing the joint-point between dedicated passenger railway and existing railwany line is the key factor influencing the operation of cross-line trains.