Purpose: This study evaluates the antioxidant and antidiabetic activities of Orostachys japonicus by considering the drying temperature. Methods: Orostachys japonicus powder was prepared by drying at room temperature (72 h), 40℃ (24 h), 60℃ (12 h), 80℃ (6 h), and 100℃ (4 h), indicated as S1, S2, S3, S4, and S5, respectively. Results: Total polyphenol content, total flavonoid content, DPPH free radical scavenging activity, ABTS radical scavenging activity, and reducing power were evaluated to clarify the antioxidant activities and antidiabetic activities of Orostachys japonicus. In all the assays, the highest values were obtained for S4 (80℃, 6 h): total polyphenol content 152.28 mg GAE/g; flavonoid content 96.01 mg RE/g; DPPH activity 71.86%, and ABTS free radical scavenging activity 42.24%. Conclusion: Our results indicate that the optimal drying conditions for obtaining the highest antioxidant and antidiabetic activities of Orostachys japonicus are 80℃ for 6 h.