The Geant4 simulation toolkit has been widely accepted in particle therapy domain for more accurate treatment planning. In Japan, the PTSIM, Particle Therapy System Simulation Framework, has been developed by the fund from the Core Research for Evolutional Science and Technology of Japan Science and Technology Agency, JST/CREST. The PTSIM provides a common platform to model beam delivery systems including a DICOM data handling for hadron therapy facility. The PTSIM can simulate existing six irradiation systems in the world and try extending the scope for clinical usage. In this paper, the performance of PTSIM is described for the use of clinical applications as a dose engine. The PTSIM was examined at the National Cancer Center (NCC) and Hyogo Ion Beam Medical Center (HIBMC) in Japan. The dose calculations had been performed on CT images with the treatment parameters determined by a treatment planning system. The dose distributions were compared with pencil beam algorithm.