In order to understand the carbon accumulation pattern under cold conditions, the primary productivity in Rhododendron aureum community in snowpacks of alpine tundra and its relationship with site characteristics in Changbai Mountain, northeast China, were investigated. Community productivity and soil nutrients were analyzed along with continuous measurements of soil temperature in different parts of the snowpacks. The snow cover in in Rhododendron aureum community lasted for over 240 days, with soil temperatures in the range -1-0℃ of 150 days, which was three times of the snow\|free. Despite the poor thermal conditions, biomass of the past three years was 1707g/m2, which was six times of that in the snow\|free area at only 288g/m2. The productivity showed a positive correlation with monthly average temperature of the coldest season or coldness index. Soil nitrogen content under snow patch was significantly higher than in snow\|free area. In addition, it was a harbor for plants to avoid injury by extreme coldness. It is concluded that the productivity in alpine tundra ecosystem depends on coldness in winter rather than on thermal conditions during growing season.