To explore the role of calciumdependent protein kinase (CDPK) in the synthesis of yam tuber starch and endogenous hormones, we used Bikeqi yam and Dahechangyu yam as the materials to determine the tuber starch, sugar, endogenous hormone contents and other indicators, as well as did the correlation analysis. The RTPCR (Reverse TranscriptionPolymerase Chain Reaction) technology has been used to clone the open reading frame of calciumdependent protein kinase gene (CDPK20). The bioinformatics analysis and subcellular location were performed. Realtime fluorescent quantitative PCR was applied to analyze the expression of CDPK20 and the correlation analysis of physiological indicators. The results showed that: (1) the open reading frame length of CDPK20 gene is 1 047 bp, encoding a total of 348 amino acids. (2) CDPK20 protein is subcellularly located in the nucleus and cell membrane. (3) The expression of CDPK20 showed a trend of increasing first and then decreasing from 105 d to 165 d after tuber planting. (4) CDPK enzyme activity was extremely significantly positively correlated with starch content, significantly negatively correlated with total soluble sugar and reducing sugar contents, extremely significantly negatively correlated with ABA, and extremely significantly positively correlated with ZR. This result suggests that CDPK is involved in the metabolism of starch and sugar in tubers and the synthesis of plant endogenous hormone ABA and ZR.