在加速器及其后的束流传输系统中,通常用一个六维相空间的椭球来表征粒子束团的真实分布,该六维椭球在任何二维子空间的投影为一个椭圆。本工作根据束流相空间的线性传输理论,推导得出了束流矩阵σ(t)的普遍表达式,并且,给出了二维束流相空间与实测束流发射度椭圆的两个半轴p和q的对应关系表达式 In the accelerator and its subsequent beam delivery systems, a six-dimensional phase space ellipsoid is usually used to characterize the true distribution of particle bunches. The projection of the six-dimensional ellipsoid in any two-dimensional subspace is an ellipse. According to the linear transmission theory of beam phase space, this work derives the universal expression of beam current matrix σ (t), and gives the two-half Correspondence between axis p and q expression