Effects of geometric parameters of diffuser vanes as well as impeller micro grooves depth on the performance of a vertically suspended centrifugal pump have been studied. Different diffuser vanes height,leading angles, trailing angles, wrapping angles and furthermore, impeller micro grooves depths have been analyzed thoroughly. Numerical results have been verified by comparing experimental data. Results, without considering cavitation, reveal that diffuser vanes height has the profound impact on the vertically suspended centrifugal pump performance followed by vanes wrapping angle. Additionally, it is observed that delivered head and efficiency of micro-grooved impellers reduce more by flow rate enhancing rather than that of the original impeller.