本文采用相空间有限元方法求解了柱形临界多群中子输运问题。其中对于方程中的坐标变量用分片连续线性多项式作为试探函数，对于方程中的角度变量用分片连续双线性多项式作为试探函数。整个求解空间区域和角度区域分别采用三角形和矩形单元划分，然后利用迦辽金方法得到一个以网格点处角通量为未知数的线性联立代数方程组，方程组中的系数矩阵的存储采用了压缩存储技术。最后用高斯消元法解此有限元方程组，表明相空间有限元方法计算收敛性较好、计算精度高。 In this paper, the finite element method of phase space is used to solve the multi-group critical neutron transport problem. For the coordinate variables in the equation, the piecewise continuous linear polynomial is used as the tentative function, and the piecewise continuous bilinear polynomial is used as the tentative function for the angular variables in the equation. The whole solution space area and angle area are respectively divided into triangular and rectangular units, and then a linear simultaneous algebraic equation system with angular flux at the grid point is obtained by using the Galerkin method. The coefficient matrix in the system is stored The compressed storage technology. At last, Gauss elimination method is used to solve the finite element equations, which shows that the finite element method in phase space has better convergence and higher accuracy.