Aiming at the uncertainty of Symplectic Geometry Mode Decomposition (SGMD) method，an Improved Symplectic Geometry Mode Decomposition (ISGMD) method was proposed. Firstly，the phase space transformation of the original time series was carried out to obtain the trajectory matrix. Then the eigenvalues and the corresponding eigenvectors were obtained by symplectic geometric similarity transformation，and a series of initial symplectic geometric components were obtained by diagonal average. Finally，the hierarchical cluster method was employed to adaptively restructure the initial symplectic geometry components to obtain the final Cluster Symplectic Geometry Component (CSGC). The experimental results indicate that the ISGMD method can effectively extract features from composite fault signals of rotating machinery and improve the accuracy of fault diagnosis.