Multilayer PCB circuit board

The utility model discloses a multilayer PCB circuit board, and relates to the technical field of PCB circuit boards. The multi-layer PCB comprises a mounting box, a placement mechanism and a heat dissipation mechanism, and a mounting cover is arranged at the top of the mounting box; the placing mechanism is arranged on the inner side of the mounting box and comprises a mounting plate and a ventilation plate, the mounting plate is fixedly mounted on the inner side of the mounting box, a rectangular hole is formed in the inner side of the mounting plate, and the ventilation plate is fixedly mounted in the rectangular hole. According to the multi-layer PCB, the distance between the two groups of circuit boards can be adjusted by installing the fixing knobs on the threaded rods in a threaded mode and rotating and adjusting the positions of the fixing knobs, contact friction of elements of different specifications on the circuit boards is prevented, the service life of the circuit boards is prolonged, maintenance