A low specific speed pipeline pump is researched to improve work performance through several certain modifications. The target is to raise the pump's head up to 80m and increase its total efficiency to 26.5% when the volume flow rate is 6.3m3/h with a rotatory speed of 2960rpm. CFD Numerical simulation is employed to predict the hydraulic performance of the pump. The volute is redesigned and splitters are imported to change the structure of the impeller. A lot of factors are taken into account, for instance number of vanes, forms of vanes, width of the volute, shape of volute's cross section, etc. These transformations ameliorate the distribution of pressure and velocity in the impeller and volute that finally increase the pump's hydraulic efficiency. The impeller trim has also been made according to the affinity law to fatherly decrease the disc friction which causes pump's mechanical loss and then achieves the optimization goal finally. It is a practical case in low specific speed pump's optimization and conclusions given at the end may be experience in the design of this sort of device.