Abstract: The objective of the study was to investigate the effects of dietary energy levels and sources on the blood metabolites, hormone secretion and the follicular fluid composition in gilt. 54 gilts with initial body weight of (59±4.2)kg were randomly allotted into six treatments. Treatments were low(L), medium(M), and high(H) feeding energy levels, which were 87.5%, 100% and 112.5% of recommendatory energy requirements by NRC, respectively, and dietary energy sources (starch, S or fat, F). Blood samples and follicular fluids were collected on d18 and d19 of 2nd estrus cycle. The results showed that circulating triglyeride, total cholesterol concentrations were higher in the fat group than that in the starch group (P<0.05), but blood glucose concentrations were similar between the fat and starch groups (P>0.05), dietary energy level had no significant effect on blood metabolites concentration (P>0.05). Gilts fed high energy level diet had a higher area under curve of the plasma insulin (Ins AUC), concentration of insulin growth factor-Ⅰ(IGF-I) and leptin than gilts fed the lower energy diet(P<0.05), but no significant difference between the fat and starch groups (P>0.05). Luteinizing hormone (LH) pulses were higher in gilts fed high energy level diet than that in gilts fed low energy level diet (P＜0.05), blood estradiol (E2) concentration was higher in fat group than that in starch group（P<0.05). Sizes of large follicles (diameter ≥3 mm) and concentrations of IGF-I and E₂ in follicular fluid were increasing significantly as the increasing energy level (P<0.05), but the numbers of large follicles and follicular fluid composition were not affected by dietary energy sources (P>0.05). The results indicated that gilts fed the high energy diet elevated blood metabolic hormones concentration IGF-I and LH secretion, and increased follicular fluid IGF-I, E₂ concentration and follicular sizes. However, gilts fed the dietary fat had a higher blood cholesterol and E₂ concentration.