The human thermoregulation study during space operation has such practical result as scientific justification of automatic thermal control system (ATCS). A primary goal is a maintenance of the thermal comfort during all possible types of human activity. It is an optimal control aim to ATCS. The main purpose of ATCS development is an identification of physiologically valuable requirements and validation of optimal laws to control human thermal status in the space suit conditions. An identification is possible only if we have a good knowledge of the control aim and current thermal status. It needs to have a criterion or assessment of interface between thermal status, actions and disturbances. The model of human thermoregulation and metabolism in space suit with ventilation loop and water cooling loop is a theoretical basis for experimental tests of ATCS. Our model has two interdependent parts: 1) anatomical/physiological compartment and 2) technical compartment. First part is presented by cylindrical human body simulator, which has core and skin layers. The skin is divided in two ventilated areas with cooling tubes or without it. Physiological compartment includes such mechanisms as perspiration, vasomotor reactions and heat production. Technical compartment includes liquid cooling garment (LCG), gas ventilation loop and space enclosure. It is represented by multi-layered envelope to isolate human against environment. This paper presents functional scheme of man rated tests for model parameters identification and its validation by analytical techniques for human thermoregulation research during space suit operations. It has provided algorithms and block diagrams of the linear model for theoretical synthesis of a purpose ATCS.