Abstract: The factors affecting cooling capacity of liquid cooled suit were discussed and analyzed from points of engineering physiology. Those are:(1) liquid temperature and mass flow; (2) cooling region and flow direction; (3) amount of moisture within the suit; (4) body activities and (5) suit structure, contact area, suit insulation and methods of wearing. These factors concerned may be considered in the proper design of liquid cooled suit in order to facilitate heat exchange between the wearer and environment.