The concept and the connotation of spacesuit ergonomics are specified. The method of ergonomics was applied to spacesuit design and the design demands for comfort, fitting and space compatibility of spacesuit are indicated systematically by applying anthropometry and building spacesuit size system (including weightlessness). Flexibility and posture of spacesuit are indicated with human mechanics (including weightlessness). The present situation of ergonomic research of spacesuit is discussed simply.