The invention discloses an overhead contact line reliability assessment method giving consideration to a weather condition, and the method gives the consideration to the impact on the reliability assessment from the weather condition, can solve a uncertain problem caused by a statistical error or insufficient data, and can be used for the reliability assessment of an overhead contact line system under different weather conditions. The method comprises the steps: 1), enabling the weather conditions to be divided into normal weather, severe weather and disastrous weather, and calculating the fault rates and repair rates of various types of elements under different weather conditions; 2), enabling the fault rates and repair rates of various types of elements under different weather conditions to serve as the random fuzzy variables, employing a triangular fuzzy number to represent the fuzzy distribution of the random fuzzy variables, and carrying out the random fuzzification processing of the fault rates and repair rates which are solved at step 1); 3), calculating the reliability index of a system giving consideration to the weather condition, deducing a calculation formula according to a GO method, and solving the mathematical expectation values of the random fuzzy variables through employing a credibility theory, wherein the reliability index serves as the reliability index of the overhead contact line system.