Criticality analysis method based on Risk Priority Number(RPN) in Failure Mode Effects and Criticality Analysis(FMECA), is usually utilized to identify risk factors, determine the critical failure mode and weak links to provide decision-making basis. In traditional RPN, the evaluation information is deterministic and the correlation of failure modes is not considered. In the actual work, the evaluators can only give uncertain evaluation information due to their own attributes and the level of understanding the evaluation objects. Usually there is correlation between failure modes, which will affect the final hazard analysis results. Aiming at the existing problems, the fuzzy RPN evaluation method based on Technique for Order Preference by Similarity to Ideal Solution(TOPSIS) for the triangular fuzzy evaluation information is studied by using the House of Reliability(HoR) to consider the correlation of failure modes. Finally, the RPN values obtained in different cases are compared with the actual case. The results show that the fuzzy RPN evaluation method considering failure mode correlation can improve the reliability of RPN value and provide more reliable basis for risk decision.