Abstract: Abstract: Household biogas is widely used in rural areas of China because it is clean, convenient and renewable energy, and the temperature of slurry in biogas digester is one of the most important factors on the biogas production. It has been proved that heating the biogas digester by solar energy is an effective manner to improve the biogas production performance of digester in winter, and many scholars have researched the thermal performance of heating the biogas digester by solar energy. The new type over-ground household biogas digester has been researched and developed successfully by Lanzhou University of Technology, which can be applied in most areas of China. In this paper, the thermal performance of the new type household biogas production system was experimentally studied in order to provide guidance for the design optimization and promotion of this type of system, which mainly included the heat collection efficiency of vacuum-tube solar water heater, the heat loss of digester and the heat transfer coefficient between hot water and slurry. The new type of system had been constructed completely in November, 2014 in a farmer family in a village of Minqin County, Gansu Province, including an vacuum-tube solar water heater with 3.85 m2 heat-collecting area which consisted of 40 vacuum tubes made of glass, an insulating room of 1.9 m × 1.9 m × 2.6 m, a rheid biogas digester of 1.6 m × 1.6 m × 2.5 m, a temperature controller, a circulating pump and other devices. After feeding 1.73 m3 slurry to the digester, the test had been done from December 1st to December 22nd, 2014, and the following parameters were measured: solar radiation on the collection face of solar water heater, hot water temperature in solar water heater's storage, ambient temperature, slurry temperature in digester, inlet and outlet temperature of heat pipe and hot water flow rate in heat pipe, which were recorded by the computer automatically. Else, in order to avoid reducing the activity of methane bacteria caused by the temperature's quick rise, the daily temperature rising was controlled within 2℃. Five days later, the slurry temperature reached up the designed value, and then was kept at (27±2)℃ when the lowest daily ambient temperature was within -9 - -18.2℃, and the average daily ambient temperature was within -2.1- -8.6℃. The results showed that, if the solar radiation on the collect area of solar water heater increased by 1 MJ/m2, the daily average heat-collecting efficiency would increase by 5.99%; if the average daily temperature difference of hot water and ambient increased by 1℃, the efficiency would reduce by 1.5%; if the average daily temperature difference of slurry and ambient increased by 1℃, the daily heat loss of digester would increase by 0.931 MJ; if the inlet water temperature increased by 1℃, the heat transfer coefficient between hot water and slurry would reduce by 0.11 W/(m2·K); the slurry temperature had significant effect on the heat transfer coefficient, and when the slurry temperature increased by 1℃, the heat transfer coefficient would increase by 0.83 W/(m2·K).