The invention discloses a sector worm-gear driven single inward-swinging bus door. The sector worm-gear driven single inward-swinging bus door comprises a door body, a door shaft, a rotary base, a crank arm, an eccentric shaft, a slideway, a mounting base, a rotary driving device of the door shaft and a safety unlocking device, and further comprises a control unit, wherein a motor drives a worm, and the worm drives a sector worm gear fixedly connected to the upper end of the door shaft to conduct positive and negative rotation, so that the inward-swinging bus door is opened or closed; the safety unlocking device keeps a worm seat equipped with the worm on the mounting base through an unlocking bolt, a spring, a pin shaft and a tension spring; and the control unit comprises a motor positive and negative rotation start-stop switch, a scram button, a position sensor for detecting whether the door body is fully opened or closed, and a PLC. In a normal state, the sector worm gear and the worm mesh with each other; in an emergency state, the unlocking bolt is pulled open manually or by an electromagnetic force, and the sector worm gear does not mesh with the worm, so that the single inward-swinging bus door can be pushed opened or closed manually and freely; and the sector worm-gear driven single inward-swinging bus door is simple in structure, convenient to operate and high in safety and practicability.