In order to investigate the impact of fulvic acid (FA) on the hydroxylysyl glycosylation in collagen bio-synthesis, 40 NMRI mice were divided into two groups (n = 20 in each group, consisting 10 females and 10 males). The animal was maintained for two generations by different diets: control group with normal water and food and study group with water containing 30 mg/L FA and normal food. The second generation of the animal was slaughtered, and the biochemical parameters of collagen content and the degree of collagen hydroxylysyl glycosylation in skin, rib and tibia were detected by biochemical methods. The mean value of collagen in the study group was increased slightly, and no significant difference between study group and control group was found (P > 0.05), but the content of glucose-glactose-hydroxylysine (GGH) was significantly decreased in the study group in comparison with the control group (P<0.01). It was suggested that through the decrease of GGH 30 mg/L FA could inhibit the activity of galactosyl-hydroxylysylglucosyl-transferase and further disturb the post-translational modification of collagen intracellularly.