The invention discloses a method for determining the distance between block valve chambers of a long-distance natural gas pipeline. The method comprises the step of collecting basic parameters of the gas pipeline, the step of analyzing related factors affecting the distance between the block valve chambers, and the step of establishing a pipeline block valve chamber distance computational mathematics model and determining the optimal distance between the valve chambers of different region grades. According to the method, firstly, the basic parameters such as the pipeline diameter, the wall thickness, the burial depth, the population density of the region where the pipeline is located, the region grade and the allowed natural gas potential emission load are collected; secondly, the third-party damage failure frequency, the failure consequence, the pipeline valve chamber design, the construction cost and the natural gas potential emission load of pipelines under different region grades are comprehensively taken into consideration, the optimal valve chamber distance calculation formula is determined, and therefore the valve chamber distance value is obtained. The method is reliable in result, easy to carry out, and a reliable method is provided for determining the reasonable valve chamber distance of the long-distance natural gas pipeline.