Abstract: Silicon doping in SPRR-300 was begun in 1980s. There are 6 tubes for silicon irradiation now. Through calculating and monitoring curb of thermal neutron fluence, target resistivity hitting ratio is high than 90%. Through spinning the silicon sample during irradiation by a rotate electric motor, uneven proportion of radial doping is controlled below 5%. Through neutron fluence rate smooth area using and silicon sample position adjusting, uneven proportion of axial doping is also controlled below 5%.