To study the effect of dietary fiber on biochemical parameters and reproductive hormones of sows, thir ty PIC sows with close parity and breeding time were randomly d ivided into 5 groups (three duplicates in each grou p), and those groups were provided respective dietary with 3%, 5% , 7%, 9% or 11% of crude fiber during pregnancy. Concentrations of serum urea nitrogen (SUN), trigly ceride (TG), and total cholesterol (TC), and glucos e (GLU) on the 28th, 60th, 104th day of pregnant were detected . The results showed that: improved level of crude fiber in the diet decreased the concentrations of SUN, TG, and T C significantly (P<0.05), but there was no signific ant effect on GLU.