In porcine production, porcine litter size is a quantitative trait and its heritability is especially low. So it is necessary to identify porcine reproductive gene and protein. The establishment of pregnancy requires performance of a receptive endometrium and ovary. The endometrium and ovary go through transformations in response to physiological changes initiated by local factors including ovarian hormones and uterine environment that make it for possible pregnancy. The endometrium and ovary secrete a wide array of growth factors, cytokines and proteins. Based on these background, we analyzed the endometrial tissue protein of porcine and would find out biomarker proteins related to porcine litter size. We sorted the two groups according to litter size of porcine: a small litter size group (SLSG) (n=2) and a large litter size group (LLSG) (n=2). The porcine endometrial tissue and ovary samples were preprocessed for proteomic analysis. In order to comparison, samples of each 2mg endometrium protein and ovary protein were separated form pI and molecular weight in the same conditions by applying a pH 3.0-10.0 IPG gels for the first dimension and then 8-16% SDS-PAGE gel for the second dimension. After proteins were visualized by staining with Commassie brilliant blue (CBB), image analysis was performed with Image Master detect variations in protein spots between large litter size group and small litter size group endometrium. And then differential proteins were identified using MALDI-TOF analysis. The master images of 2-DE gel images obtained from 2mg samples of large litter size group and small litter size group endometrial proteins at pH 3.0-10.0 revealed more than 400 protein spots in pH 3.0-10.0 range. When we analyzed the levels of expression of proteins that protein spots appeared more than 1.5-fold difference in endometrial tissue from porcine. In comparison of SLSG(small litter size group) with LLSG(large litter size group), a total of 18 protein spots differentially expressed on porcine endometrial tissue 2-DE gels, among which 9 spots were up-regulated proteins as retinol dehydrogenase 16-like isoform 1, Acrosin-binding protein, alpha-N-acetylgalactosaminidase. phosphoglycerate kinase 2, Acrosin-binding protein in LLSG. And 8 spots were up-regulated proteins as phosphoglycerate kinase 2, prenylcysteine oxidase in SLSG.