Abstract The objective of this study is to understand how humidity and temperature affect the degradation behavior of polydioxanone (PDO). After changing the degradation environments, we examined the weight loss, pH value, thermal properties, mechanical properties, morphology, and rheological properties of the PDO samples. The specimens were kept in a wet or dry condition for 12 weeks. During degradation, weight retention, pH values, tensile strength, and viscosity decreased, whereas the melting temperature () and degree of crystallinity () increased. Compared with dry samples, wet PDO samples exhibited a higher hydrolysis rate. Also, higher temperatures led to more hydrolysis. Humidity was found to decrease the molecular weight of the samples and increase the degradation rate.