Although the mud agitator is a small device among the offshore workover rig equipment, it plays a vital role in the configuration and mixing of the workover fluid (mud fluid). A high-efficiency mud agitator is the guaranteenecessary to ensure the smooth progress of the workover operation. The mixing of the mud fluid can be greatly affected by the selection of the mud agitator blades, the impeller diameter and the installation position of the impeller. The design of the mud agitator has been studied from the aspects of the impeller type, impeller diameter, blade layer number and power calculation according to the development of the standardization and modularization of the offshore workover rig in recent years. The mud agitators with different impeller diameters and different impeller configuration are simulated by using the CFD method. Finally, the product design is optimized through the comparative analysis of the flow field and power. It can provide reference for the design of the offshore workover rig mud agitator.