Abstract: The computational efficiency of the first collision method is low for large-scale mesh problems, and meanwhile there is a large calculation error in the near source region. In order to solve these problems, 3-D parallel first collision source module is developed in this paper. The spatial domain partition algorithm is adopted to improve the computational efficiency, and the adaptive source region mesh refinement technique is performed to decrease the calculation error in the near source region. The results show that the parallel computing improves the computational efficiency. The parallel efficiency can reach 66.89% when 140 cores are used. The adaptive source region mesh refinement technique reduces the calculation error in the near source region.