The invention discloses an efficient mortar spraying and plastering integrated device and a working method thereof. The device comprises a control system, a moving frame, a vertical guide rail arranged on the moving frame, a lifting frame arranged on the vertical guide rail, a transverse guide rail, a transverse scraper blade, a transverse moving base arranged on the transverse guide rail, a laser radar and a mortar nozzle, wherein the transverse guide rail and the transverse scraper blade are arranged on the lifting frame, the laser radar and the mortar nozzle are arranged on the transverse moving base, the control system is electrically connected to the laser radar, the mortar nozzle and driving mechanisms of the moving frame, the lifting frame and the transverse moving base, the transverse scraper blade, the laser radar and the mortar nozzle all extend forwards, the front side of the transverse scraper blade is located at the foremost end, the laser radar and the mortar nozzle are higher than the transverse scraper blade, the laser radar is used for detecting the distance to the right-ahead wall surface and detecting whether holes and pits exist in the right-ahead wall surface, and the control system is used for controlling the device to conduct spraying and plastering work according to a set path and adjusting the device action according to real-time feedback of the laser radar to ensure that the wall surface is sprayed flatly. The efficient mortar spraying and plastering integrated device and the working method thereof are high in working efficiency and high in precision.