The utility model discloses an automatic detection device of cement concrete pavement slab staggering quantity. The automatic detection device comprises a support, wherein a computer, a power supply, an electric motor, a first sliding rail and a second sliding rail are arranged on the support; a fixed support is arranged on the first sliding rail and the second sliding rail through a first pulley wheel and a second pulley wheel, and the upper end of the fixed support is connected with a lead screw; the electric motor drives the lead screw to move so as to drive the fixed support to move; a laser triangulation device on the fixed support moves back and forth along the central line of the first sliding rail and the second sliding rail; the laser triangulation device consists of a lineal laser, an area array CCD (Charge Coupled Device) camera and another area array CCD camera which are assembled into an integral body; the laser is dead against the ground surface; an included angle theta 1 between the first area array CCD camera and output laser in the laser is 35-50 degrees; an included angle theta 2 between the second area array CCD camera and the output laser in the laser is larger than theta 1; and the first area array CCD camera and the second area array CCD camera are arranged on the same side of the laser. The device can realize real-time, efficient and accurate detection of cement concrete pavement slab staggering quantity.