Abstract: Travel times and rays of the seismic wave are generally calculated with the ray tracing method.There are some problems in the method when a velocity model is very complex.A new method of calculating the travel times and rays is advanced in this paper.The method starts with the eikonal equation and calculates all kinds of travel times and raypaths using the reciprocity principle and fermat principle, so it solves the problems in the ray tracing calculation.It opens a new way for calculating travel time and ray of the seismic wave and the travel time inversion of the seismic wave.