In equipment quality assessment, the problems of index optimization, weight determination and selection of assessment methods are discussed. Firstly, the improved group analytic hierarchy process(IGAHP) is used to select the general performance index and the testing data index as the second index of condition assessment. On the basis of qualitative division of the quality condition, the IGAHP and CRITIC methods are used to select and analyze the third level indicators of the assessment system. After that, an improved evidence reasoning(ER) approach is proposed to evaluate the general performance indicators, the CRITIC method based on objective weight is used to reduce the dimensionality of the testing data indicators, and the results are integrated by using the improve ER approach. Finally, the validity and superiority of the proposed method are verified by an example. The results show that the IGAHP-CRITIC combination weighting method can effectively integrate the subjective and objective weight information. Optimization of indicators can reduce the dimensions and complexity of the assessment. The improved ER method considering evidence conflict can effectively reduce the uncertainty and incompleteness of the assessment.