Abstract: According to work characteristics of earth-machinery , on the basis of the accuracy problem of strength analysis results on working mechanism of earth-machinery should be improved，the paper presents an integrated and refined 3D finite element analysis for working mechanism. Taking an excavator as an example, the systematic modeling and load analysis for boom, arm, bucket, tank and connecting hinge shaft were developed. The strength finite element analysis for working mechanism was performed, and test on actual product was conducted to validate the models. The results show that this overall integrating analysis method of working mechanism can significantly reduce the calculation errors caused by simplifying and can excellently guide the design of earth-machinery working mechanism. Strength analysis method proves to be a feasible approach to solving problems of the same kind.