A monitoring device for cement pavement cracks after an earthquake, comprising a cracked pavement, a fixed plate on both sides of the crack, a support plate above the fixed plate, a strip groove on the side of the fixed plate and the support plate, and a space between the fixed plate and the corresponding support plate. The rotating shaft, one end of the fixed plate is connected to the limit plate, there are cross bars on both sides of the road surface, the distance sensor on the side of the limit plate, the elastic arc plate above the support plate, the elastic arc plate has a first through hole, and the first through hole is in the first through hole. There is a warning light, the opposite end of the support plate is connected to the lap plate, the lower side of the warning light is connected to the rechargeable battery, and there is a drainage device at the corresponding crack of the road surface. The invention utilizes the impact force, frictional force and pressure on the device during the driving of the vehicle to drive the left and right road surfaces to move closer to each other, so that the expansion speed of the crack can be slowed down during the occurrence of the earthquake, and the crack can also be repaired during the earthquake subsidence period. The service life of the damaged road surface, and the device can also drain the cracks to reduce the loss after the earthquake.