Abstract: A burnup calculation code MCRAM based on the Cinder90 burnup database was developed in this paper. The reaction cross sections of some important actinides and fission products were modified by coupling with the MCNP code. The OECD/NEA Takahama-3 PWR fuel assembly benchmark problem was used to validate the MCRAM code while a reference result was given by other codes. The results show that the relative deviation of MCRAM code calculation results for important fission products and major actinides is less than 5%. The precision of MCRAM code reaches an equivalent level of ORIGEN2 code. Meanwhile, the calculation efficiency of MCRAM code is nearly 200 times faster than MCNTRANS code while calculating the same case.