The finite element method can accurately simulate the stress distribution and deformation behavior of engineering machinery and equipment , but the premise is to use appropriate elements .More important are the boundary conditions in line with the actual situation .An improved scheme is put forward to solve the existing problems in finite element analysis on the lower structure of the crawler crane .The reasonable selection of the number , shape and arrangement of elements with less number of units , can lead to more accurate results with less calculation time .In order to accurately apply boundary conditions , the gap element is used to simulate the contact between the ground and the track .Beam elements are used to simulate the rotary supporting and the fix-ing bolts, so that the local stiffness is more close to the actual situation and the load on the frame of the distribu-tion is real .The arm operation condition , the load condition , and the turn condition are considered during simu-lation.Max boom raising , max rated load lifting and turning are the critical load case to be considered .The re-sults are compared with the measured ones , and the feasibility of this method is tested .%有限元方法能够较准确模拟工程机械局部受力和变形行为，但前提是采用合适的单元，更重要的是边界条件符合实际工况。针对履带式起重机下车有限元分析中存在的问题，提出了改进的分析方法。通过将单元数量、形状和排列方式进行配合，可以在使用较少单元数量的情况下获得较准确的结果。为了准确施加边界条件，用间隙单元模拟地面和履带的接触；用梁单元模拟回转支撑和固定螺栓，使局部刚度更接近实际情况，并使载荷在车架上的分布更真实。计算时考虑3种工况：起臂、吊载和转弯工况。将应力计算结果与实测值进行对比，大致吻合，证明了方法的可行性。
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