Abstract: In order to investigate practical effect of heat preservation of water-cooled swine bed with small groups raising of pregnant sows and low temperature in winter, sixteen pregnant sows for 4 weeks were used. Four pens were divided into experimental group and control group randomly, each pen was four sows. The door-curtain at two ends of swine bed was installed for heat preservation. The environmental temperatures for each group were measured and sows behavior was observed. The results showed that the temperatures in swine bed unit in the experimental group were 3.2 and 6.9℃ higher than that of control group and indoor temperature, respectively.