Abstract: In order to investigate the effects of microstructural and proteomic changes of fresh pork on their water holding capacity in the early postmortem period, the longissimus dorsi samples of pigs were divided into high drip loss group (H-group≥5.93%, n=3) and low drip loss group (L-group≤0.81%, n=3) according to the level of drip loss. The microstructure and proteomics of the two groups were compared. The difference proteins between the two groups were identified using Tandem Mass Tag (TMT) and intercellular spaces were observed using electron microscopy. The results showed that the extracellular space of H-group was significantly larger than that of L-group at 24 h after slaughter(P<0.01). The higher the expression level of glucose-phosphotransferase-1, heat shock protein 70 (Hsp70), ankyrin, selenoprotein W and laminin in postmortem muscle, the lower the drip loss and the better the water holding capacity, while the higher the expression level of phosphoglycerate mutase and transketolase, the higher the drip loss and the worse the water holding capacity.