The invention discloses a transformer life probability evaluation method based on generalized extreme value distribution. The transformer life probability evaluation method regards an insulation paper polymerization degree as an index on the basis of establishing a transformer insulation paper aging first-order model, simulates a healthy operation state of a transformer by utilizing generalized extreme value distribution, and calculates a fault probability of the transformer based on Monte-Carlo simulation, so as to realize transformer life probability evaluation. The transformer life probability evaluation method can effectively identify influence on transformer operation life caused by various types of uncertainty stresses during the transformer operating process, so as to improve the judgment level of an operator facing contradiction between economy and reliability during the operation and maintenance process of the transformer, assists in selecting a reasonable transformer update occasion, effectively improves the technology transformation level and economic benefit of transformers of a power enterprise, and has a high practical engineering value.