The paper aims to summarize the research status on the biodegradabilityof polybutyrolactam (PA4), as well as the biodegradation rate and degradation mechanism of PA4 and its derivatives in different natural environments such as sea, soil and compost, and provide guidance for modification and application direction of PA4. The methods of classification and summary are used to compare the degradation behavior of polybutyrolactam and its derivatives in different environments, and clarify the current research progress on their degradation mechanism. PA4 can be degraded in the natural environment in a short period of time. Its excellent biodegradability is related to hydrophilicity. At the same time, certain bacterial groups in the natural environment can secrete extracellular enzymes to hydrolyze amide bonds to degrade PA4. Structural modification also has a certain effect on the degradation rate of PA4. Exploring the changes in biodegradability of PA4 after modification will help to develop new ideas for controlling its degradation rate. PA4 has a very high application prospect as a degradable material in food packaging in the future because of its high gas barrier properties and excellent mechanical properties. It is also a difficult and hot topic in the future to realize the thermoplastic processing of PA4 by appropriate modification methods, while retaining the good biodegradability of PA4, and clarify the metabolism and degradation pathway of environmental microorganisms to PA4 and its modified products.