The invention provides an environmental sanitation vehicle and a suction nozzle device thereof. The suction nozzle device of the environmental sanitation vehicle comprises an upper top plate and a suction cavity positioned below the upper top plate, the front end of the upper top plate is provided with a front baffle positioned in front of the suction cavity, the front baffle is formed by splicingmore than two sub-plates left and right, and at least one of the sub-plates keeping right is a sliding plate which is liftably assembled on the upper top plate; and the sliding plate is connected with a driving part capable of driving the sliding plate to ascend and descend, and the driving part is mounted on the upper top plate. According to the environmental sanitation vehicle and the suction nozzle device thereof, during use, aiming at a large amount of fallen leaves collected on the right side of a road, only the gap between the sliding plate keeping right and the ground needs to be changed, the front baffle does not need to be lifted integrally, so that a large amount of airflow enters the suction cavity from the left end of the front baffle, the airflow is forced to enter the suction cavity from the gap between the sliding plate and the ground, and the suction effect when the suction nozzle device sucks the large amount of fallen leaves is enhanced.