Abstract: This paper describes a joint inversion method of the topography of seismic interfaces and lateral velocity distribution using travel times of reflections. The inverse problem is solved under the general leastsquares criterion. Two types of parameters describing interfaces and velocity needn't be seperated ahead.The numerical modelling shows that this method is effective. We have processed the Baigezhuang-Fengnan-Fengning wide angle reflection and refraction profile data using the method mentioned inthis paper and some significant results have been achieved.