The invention relates to a bridge cast-in-cantilever method cradle counter-pressure construction method, and belongs to the technical field of building construction. The method comprises the following steps: constructing a bridge foundation section, mounting cradles and a casting bottom die, manufacturing a counter-pressure mechanism, mounting the counter-pressure mechanism, placing a pressing device, regulating pressure and performing loading and detecting, and finally, realizing the actual working state of the cradle casting. The method is characterized in that by controlling the pressure of a hydraulic oil jacking device, the base die is downwards pressed, a hanging rod is upwards pulled, the actual stress of the cradles is simulated, and the deformation parameters of each part of each cradle are measured, so that the reliability of the cradles is verified, the non-elastic deformation of the cradles is eliminated, and the formwork erection elevation is convenient to correct. The method disclosed by the invention overcomes the defects of a traditional preloading method and can be used for accurately simulating the actual stress situation of the cradle construction in the cast-in-cantilever method, and the method has the advantages of easy control of preloading, high safety, good stabilization, time conservation, labor conservation and lower cost. The method can satisfy the requirements of various kinds of cast-in-cantilever construction.