Abstract: In studying the properties of thermodynamic cycle of metal elements author has derived a general equation: ΔX=2π/270_xΦ_i·R_xwhere ΔX: ΔH_i⁰,ΔG_i⁰,ΔS_i⁰; x^Φ_i: practical radian; R_x: practical radius of the cycle. A calculating scale of thermodynamic cycle of metal elements has been designed on the basis of this equation. The scale can be used for calculation of 66 kinds of thermodynamic data.The structure and some applications of the calculating scale have been briefly described.