Abstract: A conveyor belt lifting mechanism which includes an L-shaped arm, a telescopic arm, and a supporting shaft and an online operation and maintenance robot for a pipe belt conveyor are provided. One end of the L-shaped arm is rotatable, an axial direction of a rotating shaft is parallel to a conveying direction of a conveyor belt, the telescopic arm is slidably connected to the other end of the L-shaped arm, and the telescopic arm extends and retracts in an extension direction of the L-shaped arm. A universal rotary driving portion is connected to an end of the telescopic arm, the supporting shaft is fixed to an output end of the universal rotary driving portion, and two supporting rollers are arranged on the supporting shaft. An included angle between rotating shafts of the two supporting rollers is the same as that between two adjacent idlers in the pipe belt conveyor.