A Monte Carlo code applied to radiation protection and medical radiology is presented. It simulates the irradiation caused by photons and can give the effective dose equivalent (H_e)and absorbed dose equivalents of 20 organs (tissues) in a reference man. A special method which divides all photon histories into several kinds and traces each kind separately was adopted to improve the precision of the calculated results.The code can be also used to other calculations of doses in systems with complex geometry.

ORIGEN-2 is a versatile point depletion and decay computer code. Its functions, major charactaristics, and theoreticahmodels are briefly introduced in here. The transplantation of the code on IBM 4300 series computers and its augmentation of output photon data and application in calculating gamma-ray spectra of fission products are described.