To study the fracture speed of power turbine blades in aero-engine and its variation law with the proportion of bending stress, a total of 32 simulated blades with 4 different ratios of bending stress were designed and processed based on the principle of equivalence. The fracture speed of the simulated blades was calculated by finite element method. The simulated blades were grouped and fracture speed measurement experiments were conducted to obtain the actual fracture speed and fracture form of the blades. The simulated blade fracture test process was recorded by high-speed camera technology, and the variation law of blade fracture speed with the proportion of blade bending stress was obtained. The research results show that the error between the actual fracture speed and the calculated speed of the simulated blades are not greater than 1.10%. Within a certain range, as the bending stress decreases, the fracture speed of the blade generally shows a downward trend, and as the proportion of bending stress in the blade increases, the fracture speed of the blade decreases faster. The research provides a reference for the strength design and blade fracture test methods of real blades, which has important engineering application value.