Winter turnip rape (Brassica rapa L.) is a valuable ecologically beneficial oil crop that is produced mainly for its ability of conserving soil and water in winter and spring and its high quality edible oil in northwestern China. However, coldness and extremely low temperature negatively affects the growth and development of winter turnip rape, resulting in failure to overwinter and production in northwestern China. ‘Longyou 7’(Brassica rapa L.) and ‘Tianyou 4’ (Brassica rapa L.) are closely related plant species, but their cold tolerances are different. ‘Longyou 7’ is a cold-tolerant cultivar, ‘Tianyou 4’is a cold-sensitive cultivar. In this study, we used iTRAQ-based proteomics to compare quantitative changes in the proteome of two winter turnip rape leaves and roots in response to cold stress to elucidate the possible molecular mechanism underlying the ability of ‘Longyou 7’ to adapt to cold stress.