Abstract: Radiation shielding calculation of nuclear facilities has always been one of the difficulties in engineering application of Monte Carlo method for its large scale calculation and deep penetration characteristics. Two international benchmarks, published by OECD, Winfrith Iron/Water Benchmark Experiment(ASPIS), were simulated based on the three-dimensional Monte Carlo transport code JMCT, accompanied by a visual modeling tool JLAMT. The simulation includes detailed modeling and shielding calculation. Calculated results were compared with experimental data, also with almost same results achieved by MCNP. The comparisons show that the calculated results agree well with the experimental data. The maximum deviation of JMCT and MCNP is below 20% and the average deviation is less than 10%. It is proved that JMCT code suits well for shielding simulation and deep penetration problems.