The invention discloses an elevator car manned space detection method. An elevator car current image is transmitted to an image comparison system through an image capturing device and is compared with a standard comparison image; the usage rate of the internal space of a current elevator car is obtained by calculation and is transmitted to a control system; the control system calculates and analyzes a received signal and judges the usage state of the internal space of the elevator car; the usage rate of the internal space of the elevator car can be accurately calculated according to comparison of the elevator car current image and the standard comparison image; and the control system can conduct corresponding operation control according to the use condition of the internal space of the elevator car and data of an elevator car weight detection device. An elevator car manned space detection system can achieve high-precision detection of the available space of the elevator car, the system structure is simple, the detection result is reliable and high in stability, a reliable evidence can be provided for control calculation of full load pass non-stop, group control allocation and the like of an elevator, the elevator operation efficiency is improved, and better riding experience is provided for passengers.