Working condition and structure for crane boom is quite complex. In order to ensure the safety of crane, there is a high requirement for reliability. In this paper, probabilistic finite element method is used to analyze the reliability of crane boom. Parametric finite element model of crane boom is built and uncertain parameters are obtained by analyzing characteristics of dimensions, materials, loads and constraint conditions for crane boom. Uncertain parameters like structural dimensions, material parameters and loading parameters, etc are processed discretely and reliability of crane boom is obtained by using Probabilistic Design System (PDS) of ANSYS. Meanwhile, we can get the main parameters which affect reliability of crane boom and how much their influences will be by sensitivity analysis.