With the development of commercial spaceflight, microsatellites gradually occupy more and more market share. In order to meet the demand for small-size, low-impact, fast-response connection and separation of microsatellites, this paper designs a low-impact connection and unlocking device based on a cam-linkage mechanism with a single firework and multi-point compression. The trigger system and transmission system design method of the device are studied. The static strength calibration is carried out through ABAQUS for the connection bearing capacity, the unlocking motion process is analyzed through ADAMS, and finally the unlocking performance is verified through tests. The results show that the device has small unlocking impact, fast response, good unlocking synchronization, and has great potential for application in small satellite rocket-satellite separation.