Abstract：One of the major troubles involved in wave equation inversion is too much computation. An effectual fast iteration method for inversion of physical parameters of stratified medium is recommended here. On the basis of source function transform (literature 1), this method neglects multiple influence and takes primary reflection or secondary reflection as approximate synthetic seismogram to solve for gradient matrix. In spite of slight more iteration times, this method needs much less computer time than the original method that makes difference operation to solve for derivative and gradient matrix. It is experimentlly proved that this method is very efficient to speeding up inversion in stratified medium.
