A water jet splitting chamber for waste tires has a chamber body, a water jet module, and an actuator. The chamber body has a retaining wall located in the chamber body to divide the chamber body into a splitting space and an actuator space. The water jet module is mounted in the splitting space, and has a slide seat mounted on the chamber body and at least one water jet seat mounted on the slide seat and being capable of linearly moving along a mounting direction of the slide seat. The actuator is mounted in the actuator space, and has a motor and multiple linking rods. The multiple linking rods are driven by the motor and extend into the splitting space, extending directions of the multiple linking rods are along the mounting direction of the slide seat, and the water jet heads face toward the multiple linking rods.