Quantifying human health status and avoiding possible exercise risks in advance effectively and reasonably during exercise are the urgent problems to solve. In this paper, first, by mathematical modeling of human thermo-regulatory mechanism and heart rate regulatory mechanism, a human exercise thermo-physiology simulation model was proposed, by which multivariate physiological data such as core temperature, sweat rate, and heart rate can be simulated. Second, in order to effectively predict human exercise status, a specific fuzzy finite state machine based on the simulated physiological values was defined and a health status probability calculation model for health status quantitation at any time during exercise was established. The experiment results show that there is a same trend between the simulation results and experimental results, and the proposed method is of great value in analyzing and predicting of health problems in the process of exercise simulation.