This paper investigates and analyzes the pollution diffusion of exhaust-gas system from cooking in a closed kitchen with a range hood,the effects of the location of a kitchen-stove,the height of the range hood,and the gear of the range hood on the diffusion and on the human life.With the Data Fit method and experimental data,establish the distribution mathematical models of the exhaust-gas concentration and the exergy and the total exergy intensity.Make software with VC++ visual programming techniques to simulate the pollution distribution laws,and compare the simulation results to actual test results.The authors present the pollution distribution figures and tables of simulation results and experimental test results in CO2 and CO concentration,exergy,and exergy intensity.The research shows that the exhaust-gas diffusion has laws and direction; and it is possible for us using VC++ to simulate the diffusion laws numerically at certain boundary and certain conditions for a kitchen buming liquefied gas.This research will be of an important meaning in the field of how to eliminate polluted gas from the kitchen.