The invention discloses a system for measuring the distance between an elevator lift car sill and a well inner surface. The system comprises a data acquisition system, a data processing system, an auxiliary system and a display system, wherein the data acquisition system, the data processing system and the display system are sequentially connected. The auxiliary system comprises a power source and a control circuit, the data acquisition system comprises a laser displacement sensor, a signal of the laser displacement sensor is processed through the data processing system, and displacement data are obtained and then displayed through the display system. According to the system, a maximum value and a minimum value which are measured within a certain period are filtered through the filtering processing technology, other points are weighed to solve to obtain an average, and accurate data can be obtained; an analog signal is output through the laser sensing technology and then converted into a digital signal to be processed through a single-chip microcomputer, and the system has the advantages of being high in efficiency and accuracy, easy to operate and convenient to popularize and use.