Objective To strengthen the quality control management and enhance the detection capacity of the experimental animal quality control laboratoriesin our country through the detection of serum esterase-1 (Es-1) in the experimental mice. Methods The samples were prepared according to the standard procedure, and then were randomly numbered and distributed to participating units by cold-chain transport. Before the deadline, the participants submitted the results and the copies of original records. When the results were completely consistent with the standard results,the results were regarded as satisfactory, otherwise were unsatisfactory. Results A total of 11 laboratories participated in this program, of which 10 laboratories were regarded as satisfactory (90.9%) and one laboratory obtained unsatisfactory result (9.1%). Conclusions The results of this proficiency testing project demonstrate that the overall detection level of Es-1 in laboratory mice is highof the participating laboratories. However, more attention still should be paid to standard specifications and some test details.