The invention relates to the technical field of petroleum equipment, in particular to an efficient mixing system for well cementing operation. The efficient mixing system comprises a measuring tank, aclear water manifold assembly, a cement grey feeding manifold assembly, high-energy mixers, a mud mixing tank and a mud manifold assembly. The mud mixing tank is at least connected with two high-energy mixers, and an inlet of the mud mixing tank is connected with diffusion boxes which are connected with the high-energy mixers. Discharged materials of the high-energy mixers are guided into the mudmixing tank through the diffusion boxes, and the at least one diffusion box is connected with a density control system. The multiple sets of mixers are integrated, and the large-discharge-capacity and efficient mixing effect can be achieved with existing operation conditions.