A microwave resonant cavity for laser cooling, microwave interrogation, and atomic state detection, comprising a microwave resonant cavity body, two cutoff waveguide end covers, and four waveguides for laser beams and microwave coupling. The cavity feeds not only microwave but also laser beams into the center of the cavity. In a vacuum chamber with target atoms, the target atoms may be trapped and cooled in the center of the cavity. By sequential operation of the resonant microwave and lasers, the microwave resonant cavity of the present invention may manipulate and detect the atomic state population and interrogate the energy level of the cold atoms in situ. The invention may be applied to the fields of atomic frequency standard, interferometer and atomic gyro for developing the miniaturized cold atoms related precision measurement equipment.