Abstract: OBJECTIVE To evaluate the safety of alfalfa transformated with HBV antigen protein gene (ATHAPG) for its further research. METHODS Systematic safety was evaluated by acute toxicity and genotoxicity experiments including V79/HGPRT gene mutation test, mice bone marrow micro-nuclear test, Ames test and mice sperm abnormality test. RESULTS The maximal tolerance dose was higher than 10.0 g·kg^-1, all genetic toxicity tests were negative. CONCLUSION ATHAPG is an actually non-toxic substance. ATHAPG has no mutagenic effects under the experimental conditions.