To study the effect of ventilation mode on indoor thermal environmental parameters in winter in cold zone, the realizable k-ε turbulent model of CFD was adopted to numerically analyze the airflow field, temperature field and thermal comfort of a residence in Lanzhou when the unsteady heat transfer through outerwalls was considered. Three types of ventilation modes were obtained on the condition that the indoor heating temperature was ensured and the indoor air quality was improved simultaneously. Comparing the indoor characteristics of airflow field and temperature of the three types of ventilation modes, we analyzed the thermal comfort in different rooms subsequently. And the thermal comfort results indicate that the indoor environment feels a little cold for all the three feasible ventilation modes.