Based on the research status of the testing method of structural displacement，we propose the idea of measuring dynamic displacement of wharf without benchmark，and establish the corresponding test and analysis system. We select the passive servo sensor to collect the dynamic signal，and study vibrational response law of the sensor to different loading forms by the simulation test system，propose a correction method to obtain actual value of structure displacement based on inverse analysis by the simulation model of the test system and signals of sensors aiming at the working condition of quasi-static displacement，develop the dynamic displacement testing technology without benchmark for dock structure under variable load，and carry out field dynamic displacement test to verify the reliability of the proposed technology combining with the research on wharf displacement limit based on comfort level and the analysis and calculation of finite element modeling. The results show that the technology is simple to operate，reliable in results，less affected by the environment，and can realize remote automatic monitoring