Abstract: Biological shield is one of the most important source items in a reactor. The activated products distribution in biological shield of SPRR-300 reactor was obtained by using MCNP and ORIGEN2 program to set up calculation model. Some concrete samples from biological shield of SPRR-300 reactor were analyzed. The analysis results show a good agreement with calculation result, which proves that the calculation model is accurate. The activated thickness for ⁶⁰Co in biological shield is confirmed through the fitting of analysis results, which is 840 mm in 1.1 m height position and 680 mm in 1.5 m height position.