Objective To observe the NTBC dependence of Fah-knockout mice and study the biological characteristics in order to use the model more effectively. Methods Examine the progressive changes in body weight, survival time, liver pathology and serological markers after the NTBC withdrawal. Results After removing of NTBC, Fah-knockout mice lost their body weight gradually, and finally died in 5 to 7 weeks, along with increased serum ALT, AST levels and deformation of the hepatocytes. Conclusions Fah-knockout mice have a strong drug dependence of NTBC and could be the ideal model to hereditary tyrosinemia type I and other liver injury.