With the high-speed railway put into operation, the types of trains in the existed line is reduced, train intervals will also be shortened. We analyze the impact of high-speed rail's operations on the basis of the calculation method of the interval passing capacity in existed line, for example in three major areas : the difference of train running time in the section, the proportion of trains dispatched in succession, the change of train tracking interval. From the definition of the removal coefficient calculation, we calculate the existing railway single line and double line transport capacity after release.