Due to the extensive use and improper recycling of traditional plastics, more and more policies have been issued to manage and restrict the use of traditional plastics. Therefore, Biodegradable Plastics (BPs), a substitute of traditional plastics, are widely used in daily life. However, it cannot reach the expected degradation effect in the natural environment, BPs may produce micro-plastics faster than traditional plastics called Biodegradable Microplastics (BMPs). In order to explore the degradation of BMPs, we designed a degradation experiment of BMPs under Ultraviolet (UV) radiation for 64 days. The results showed that the surface of BMPs gradually became rough with the aging time. And the both slight increase of O/C ratio and CI (carbonyl index) value of them indicated that they were oxidized under UV radiation. In addition, the crystal behaviors and the thermal stability of BMPs showed no obvious changes before and after aging. Our findings demonstrated that BMPs were less sensitive to UV radiation as compared with those of conventional plastics, giving evidence that it is necessary to increase regulation and constraints on their upstream production and subsequent disposal to achieve their environmental friendly purpose.