Abstract：In order to study the preciously imaging method of seismic data in conditions of relief surface,complex structure and velocity distribution,the paper used finite-element algorithm to finish the wave-equation reverse-time extrapolation of surveyed wavefield,and proposed taking the time the max amplitude appeared in node wavefield for the imaging condition of max amplitude,which is different from the imaging condition of shooting time.This imaging condition is based on the wave theory rather than on ray theory,which can focus energy better.The finite-element method used 6-node triangular element,quadratic interpolation of field and velocity in element is carried out to improve the precision of simulation; Diagonal lumped mass matrix was used to replace consistent mass matrix to avoid matrix inverse and improve computation efficiency.It's shown by computing three theoretical models: sag model with topography,Marmousi model and Marmousi model with topography that the method can effectively handle the issue of seismic imaging in complex geologic condition.The imaging in such complex geologic bodies as fault,faulted block,anticline structure,high-velocity body and targets is characterized by identification and accurate position.Especially,the imaging results of model data based on ragged surface by direct migration are also better.
