Abstract: Housing system is a popular mode applied widely in current pig production industry, which has many advantages, such as occupying less land, feeding and managing easily, and realizing environmental control in some extent, but the pig welfare is difficult to be guaranteed because the housing environment is relatively poor. The relations between the pig welfare and the related impact factors in pig housing system are discussed worldwide, the negative impacts of the poor animal welfare under housing conditions are analyzed. Finally, the necessity in enhancing investigations on pig welfare in housing system in China is presented, and the measures as well as suited equipments for improving pig welfare are reviewed based on the current national and international researches. The paper gives some ideas in the aspects of durative and healthy development of China pig industry and also in how to improve the international competitive capability of China pig production industry in future.