The invention discloses a stone crusher with energy-saving and noise-reducing functions used for mine construction. The stone crusher comprises a rectangular frame, a U-shaped guide plate, a door-shaped frame, an H-shaped hanging plate, a multi-section telescopic rod, a balance weight circular truncated cone, an upper pressing plate, a lower pressing groove seat and a driving part. According to the stone crusher, the rectangular frame, the U-shaped guide plate, the door-shaped frame, the H-shaped hanging plate, the multi-section telescopic rod, the balance weight circular truncated cone, the upper pressing plate, the lower pressing groove seat and the driving piece are arranged, the upper pressing plate and the lower pressing groove seat are used for crushing stones, an L-shaped plate is arranged at the bottom of the multi-section telescopic rod, the top of the multi-section telescopic rod is connected with the balance weight circular truncated cone, the H-shaped hanging plate ascends to carry the balance weight circular truncated cone and one end of the U-shaped guide plate to ascend, when the H-shaped hanging plate ascends to a certain height and pushes away the balance weight circular truncated cone, the balance weight circular truncated cone moves outwards along the inclined U-shaped guide plate and then drives the L-shaped plate to rotate, the L-shaped plate rotates to push the upper pressing plate to move downwards, and therefore crushing machining of the stones can be achieved, potential energy is utilized for crushing machining, and the energy-saving effect is achieved.