本文提出了用极坐标系中的Ｂ样条有限元法解波导本征值问题．该方法有两个突出优点：（１）避免某些含曲线边界的波导截面的剖分误差；（２）改善尖角波导的计算精度．本文首先建立了极坐标系中Ｂ样条有限元方程，然后通过对圆形、扇形、双脊圆形和心形波导本征值问题的实际计算，表明方法的有效性和实用价值． In this paper, the problem of eigenvalue of waveguides by B-spline finite element method in polar coordinate system is proposed. This method has two outstanding advantages: (1) to avoid the segmentation error of waveguide cross-section with some curved boundaries; and (2) to improve the calculation accuracy of sharp-edged waveguide. In this paper, we first establish the B-spline finite element equation in polar coordinate system, and then show the effectiveness and practical value of the method through the practical calculation of the eigenvalue problems of circular, sector, double ridge and waveguide.