文中针对桁架结构研究了基于概率的结构动力特性分析方法。首先建立了结构材料的物理参数和杆长尺寸两者之一或同时具有随机性时结构的刚度矩阵和质量矩阵 ,再从结构振动理论的瑞利商表达式出发 ,利用代数综合法推导出结构特征值随机变量数字特征的计算表达式 ,并提出了求解方法。最后通过两个算例考察了结构物理参数和几何尺寸的随机性对其动力特性的影响 In this paper, based on the truss structure of the study based on the probability of dynamic characteristics of structural analysis. First of all, the stiffness matrix and mass matrix of the structural material with both physical parameters and rod length or random structure are established. Then from the Rayleigh quotient expression of structural vibration theory, the structure is deduced by the algebraic synthesis method The eigenvalue calculation formula of the digital characteristics of random variables is proposed and the solution method is proposed. Finally, two examples are used to investigate the influence of the randomness of structure physical parameters and geometrical dimensions on the dynamic characteristics