The invention discloses a key module structure. Each key module structure comprises a bottom board, a circuit board, an elastic body and a keycap from the bottom up in sequence, wherein the bottom board and the keycap are fixed through a scissor pin; meanwhile, the elastic body passes through the scissor pin to support the corresponding keycap; each scissor pin comprises an outer scissor pin and an inner scissor pin that are matched mutually; each of the two sides of each bottom board extends from the surface upwards to form a section and then is bent to form a clamping hook; each clamping hook is equipped with a first hook groove and a first contact surface; correspondingly, a groove capable of accommodating the clamping hook is formed in each of the two sides of the lower end of the outer scissor pin; one end of the corresponding groove is bent to form a second hook groove; meanwhile, the groove has a second contact surface; the bending directions of the corresponding first hook groove and the corresponding second hook groove are opposite; the corresponding first hook groove and the corresponding second hook groove are buckled mutually; and the corresponding first contact surface and the corresponding second contact surface are matched mutually to finish the rotation connection of the corresponding outer scissor pin and the corresponding bottom board. According to the key module structure, the structure of the bottom board is simplified, and the open pores in the bottom board are reduced, so that the keyboard strength is reinforced and the service life of the keyboard is prolonged.