The temperature control precision demand in artificial environment experiment chamber was lower than the demand in technical environment. If the heating mode of split air conditioner was adopted to control temperatures in chamber in winter conditions, the fluctuation scale of the temperatures in the chamber was too large, which affected the accuracy of data recording. A new method was proposed to stabilize temperatures in artificial environment experiment chamber in winter conditions combing cooling mode of the split air conditioner with an electric heater. In the background experiment, the new method and the control method of heating mode of traditional air conditioning were compared and the results showed that the new method could greatly improve the temperatures stability in the artificial environment experiment chamber. A series of additional experiments were implemented to further study the relationship between the temperature setting of air conditioner in cooling mode and the power of heater. The experimental results showed that there was a matching relation among the cooling capacity of air conditioner Q₁, heating load of the testing room Q₂, power of electric heater Q₃, and the power of other equipment in the testing room Q₄. The air temperature fluctuation in artificial environment experiment chamber was more stable and smaller, when the absolute value of Q₁+Q₂-Q₃-Q₄ was lower under the same setting temperature of air conditioner in cooling mode.