In the crime of drunk driving, the expert opinion of blood alcohol content has become the main basis for conviction. In the court interrogation, the driver and his defense attorney have also raised objections to the expert opinion, mainly including the procedure, method, subject and standard of application of the expert opinion, and the judge’s attitude towards the objection is mostly non adoptable or supportable. The main reasons are related to the authority of appraisal bodies and appraisal opinions, the inadequacy of the party’s argument on objections, the dependence of judges on appraisal opinions, and the slow and inadequate ideological transformation. Based on this, we should standardize the procedure of blood sample extraction and identification, strengthen the implementation of applicable norms for identification, standardize the regulation and management of identification institutions and experts, avoid the problem of integration of investigation and identification, and strengthen the transparency of identification procedures, which is conducive to better standardize the identification procedures and enhance the evidentiary capacity of expert opinions.