The invention discloses a method for estimating plane strain breaking tenacity KIC of high-strength steel, belonging to the technical field of the breaking tenacity of metal materials. The method comprises the following three steps: measuring yield strength sigmay of the high-strength steel by virtue of a tensile experiment; measuring the impact tenacity alphak of the material by virtue of a room-temperature Charpy impact test; and accurately calculating KIC according to an intrinsic relation between the impact tenacity and the breaking tenacity of the high-strength steel. According to the method, the breaking tenacity of the high-strength steel can be simply, rapidly and conveniently estimated, so that the test time and cost are greatly saved, and the method has important reference significance to the material in which KIC cannot be measured in a breaking tenacity standard test. By virtue of the rapid estimation of the breaking tenacity, accurate reference is provided for the materialselection in engineering application, and particularly reliable performance index is provided for the damage tolerance design of high-strength steel structural components such as aerospace and petroleum transportation pipelines and nuclear power plant pressure containers.