Abstract: This paper describes the design of buoyancy adjusting mechanism,pitch adjusting mechanism and roll adjusting mechanism of an underwater glider,and analyzes the relationship between its movement mechanisms and motion performance.The underwater glider motion performance is analyzed by a method using CFX hydrodynamic calculation software.The hydrodynamic parameters of constant gliding motion are identified with least square method based on CFX calculation results.The space helix turning motion is simplified,and a method for analyzing the turning characteristics and estimating the turning circle radius with CFX hydrodynamic calculation is presented.