Objective To observe the changes and possible mechanism of intestinal permeability in pigs without direct injury after abdominal intestinal firearm penetrating injury in plateau cold environment. Methods 55 experimental pigs were divided into two groups: plateau cold group (HC) and plain normal temperature group (LN). According to the observation time, each group was divided into five experimental subgroups: 0h, 2h, 4h, 8h and 24h. There were 6 pigs in each subgroup in HC group and 5 pigs in each subgroup in LN experimental group. According to the time point of euthanasia, intestinal tissues were taken and the levels of inflammatory factors TNF- α, IL6 and IL-10 in intestinal homogenate and the concentrations of intestinal permeability related proteins DAO and D-lactic acid in blood were detected by ELISA method. The intestinal tissues of experimental pigs were taken at LN-0h, LN-8h and HC-8h time points, and the intestinal pathological changes were observed and scored after HE staining. The contents of Occludin, ZO-1, Claudin-3 proteins related to intestinal permeability and TLR4, NF- κ B and MLCK proteins related to intestinal permeability were detected by WB method to explore the effect of cold environment at high altitude on secondary intestinal permeability changes after injury and its possible mechanism.