A commercial vehicle cab roof structure comprises a front roof, a middle roof and a rear roof. The front roof, the middle roof and the rear roof are connected in sequence, the rear roof is higher than the middle roof, the middle roof is higher than the front roof, a skylight opening is formed in the middle of the middle roof, the front roof is connected with the middle roof through a front lap-joint edge and an upper middle lap-joint edge, the middle roof is connected with the rear roof through a lower middle lap-joint edge and a rear lap-joint edge, the front lap-joint edge and the upper middle lap-joint edge are connected to form a flow guide groove, the lower middle lap-joint edge and the rear lap-joint edge are connected to form a flow guide groove, a plurality of middle reinforcement ribs are arranged at the positions, close to the left side edge and the right side edge, of the middle roof, and a plurality of rear reinforcement ribs are arranged at the positions, close to the left side edge and the right side edge, of the rear roof. The commercial vehicle cab roof structure is low in production cost and low in welding difficulty, rain is not prone to being leaked, wind resistance is small, and energy consumption is low.