SCL3 cryogenic plant had short maintenance period from July 2023 to September 2023. We filled oil for helium compressors, cleaned several filters including inlet filter of cryogenic turbine, inspected pressure safety valves based on KGS regulation and so on. We finally conducted helium conditioning for contaminated location by air. The items for maintenance were decided based on our operation experience for one year. In this paper, the detail of items, issues during maintenance and the result of maintenance will be discussed.