A ninety-day feeding trial was carried out to investigate the effect of protein on growth and serum biochemical Indexes of juvenile Tibetan macaque. Diets with five levels of protein (11.1%, 16.1%, 20.5%, 24.5% and 29.8%) were fed to Tibetan macaque. The results showed that: weight gain, serum albumin, globulin increased with the increasing protein levels (P < 0.05). Activities of serum aspartate aminortransferase, alanine aminotransferase and urea nitrogen were significantly improved in response to the increasing levels of dietary protein. But there was no significant difference in serum total protein, triglycerides, Gamma-irradiation glutamine shift enzyme and alkaline phosphates among these groups. The dietary protein requirement for weight gain of juvenile Tibetan macaque pestimated by brokenline model was 23.69%.