The invention provides a distribution network equipment health degree dynamic diagnosis method involving credibility evaluation. The method comprises the following steps: step (1), obtaining an original feature set of power distribution monitoring quantity; step (2), determining an important status variable through correlation analysis for information of failure equipment and non-failure equipment; step (3), carrying out data quality pretreatment on data of the important status variable determined in the step (2); step (4), marking the important status variable after treated in the step (3); and step (5), inputting a marking result of the important status variable into an evaluation model, and obtaining an evaluation result. The phenomena of data collision and data redundancy appearing in the process of collecting equipment status variables are solved through data credibility evaluation and fusion of different criterial evaluation results, and meanwhile self-updating of the evaluation model is realized through dynamic regulation, so that the method is applicable to power distribution networks with constant development and change.