Abstract: A modeling method for computing of sound radiation of target in ocean acoustic environment is proposed based on wave superposition method,applying different underwater acoustic propagation models in near and far fields,which can analyze efficiently near and far fields as a unified system.With given surface velocity potential of target,virtual source strength within the target can be calculated.By using these source strength and the Green function which stands for sound propagation model of point source in the corresponding underwater environment,the acoustic radiation field outside the target can also be calculated,where image-source method is used to achieve source strength and acoustic radiation field in near field while normal-mode method is applied in far field.Through the calculation for acoustic radiation field of pulsatingsphereand oscillatingsphere in finite depth with positive velocity gradient,negative velocity gradient,and negative thermocline velocity gradient,the results will be compared with the finite element results from COMSOL software.This method is proved of the computational efficiency while it guarantees the precision of calculation.