A radiation transport calculation can derive dose distribution in a heavily exposed person for the medical treatment at the case of an accident. Since the accident cannot be prospected, many complicated procedures are needed to make the input file soon after the accident and to inform radiation dose based upon the output files with much information concerning the calculation. Thus, \(\underline{Ra}\)diation \(\underline{D}\)ose \(\underline{A}\)ssessment system for \(\underline{R}\)adiation \(\underline{Ac}\)cident (RADARAC) was developed to derive effectively radiation dose by the MCNPX or the MCNP code. RADARAC consists of RADARAC\_INPUT and RADARAC\_DOSE. A user can interactively set up necessary resources to make input files with three programs in RADARAC\_INPUT. The results of radiation doses are indicated with tables, graphs and figures depicting dose distribution by RADARAC\_DOSE. It is confirmed that RADARAC can make input files with a few thousand lines and indicate more than 20,000 data dose within a few minutes.