Abstract: An increased frequency of extreme climate events is one of the important characteristics of global climate change. Extreme low temperatures not only affect agricultural production, but also affect agricultural carbon emissions. Soil respiration, is the main source of agricultural carbon emission. However, there has been a lack of detailed study of soil respiration at extremely low temperatures. Through measuring soil respiration and hydro-thermal factors under low temperature in winter, we analyzed the response characteristics of soil respiration in the extreme low temperature environment. There were 6 treatments: TA (no straw mulching+Chinese milk vetch monoculture), TR (no straw mulching+rape monoculture), TAR (no straw mulching+rape intercropping with Chinese milk vetch), SA (straw mulching+Chinese milk vetch monoculture), SR (straw mulching+rape monoculture), SAR (straw mulching+rape intercropping with Chinese milk vetch). Results showed, soil respiration and root respiration reached to maximum in the SAR treatment. Chinese milk vetch significantly increased the soil temperature, soil moisture and soil electrical conductivity in the depth of 10 cm. In addition, compared with ordinary low temperature environment, the extreme low temperature environment decreased significantly the soil respiration and root respiration, increased significantly the temperature sensitivity of soil respiration (Q₁₀ value) from 0.31 to 1.19, and changed the relationship between soil respiration and soil electrical conductivity. At the same time, the proportion of root respiration in the TA and TAR treatments were increased by 12.07% and 8.15%, however, the proportion of root respiration in the SA, SR and SAR treatments were decreased by 28.55%, 38.87% and 24.80%.