Objective To establish the background information of physiological parameters for germ-free (GF) Taihu piglets. Methods In this study we selected 25 days old GF Taihu piglets and 4 conventional (CV) littermates, the male and female ratio was 1∶3, to measure the normal clinical values of hematology and serum biochemistry, immunoglobulin concentration and main organ coefficients. The analysis of relative growths of main organ weight to body weight was conducted in the Taihu GF and CV pigs by allometric scaling model.Results (1) Twelve hematological parameters and 8 blood biochemical parameters in the GF piglets were significantly lower than those in CV pigs (P<0.05). (2) The average body weight, IgM concentration of GF pigs and CV pigs had significant difference (P<0.05), and no mesenteric lymph nodes were found in the GF pigs. (3) The gut weight had the largest allometric association with body weight in the GF pigs, while spleen weight has the largest allometric association with body weight in the CV pigs. Both the weight of heart and stomach in CV and GF pigs had a negative allometric association with body weight (allometric coefficient b<1), respectively. Conclusions Different microbe control grades affect the body weight, hematology and serum biochemistry, expression of immunoglobulin and development of main organs in laboratory pigs.