Abstract: The present invention discloses an integrated composite overload injection system and a working method thereof. The feeding mechanism preliminarily mixes water with a main agent and an auxiliary agent of an intelligent energy-gathered oil-displacing agent according to the ratio, the outlet of the feeding mechanism is communicated with the input port of the composite overload mechanism through a pipeline, the composite overload mechanism stirs, mixes, dissolves and overload ripens the preliminarily mixed solution to form mother solution, the mother solution is input from the output port of the composite overload mechanism to the inlet of the booster pump through a pipeline, the booster pump injects the boosted mother solution into the mixer, the mixer mixes the mother solution and the diluted high-pressure water and injects it into an oil-water well, and the power shafts of the composite overload mechanism and the booster pump are both driven by the driving mechanism.