Article 14, paragraph 6 of the Regulations on Work-Related Injury Insurance provides that an employee shall be ascertained to have suffered from work-related injury if he is injured in a traffic accident on his way to or from work for which he is not principally responsible. In practice, the traffic control department of the public security organ has the legal duty to handle traffic accidents and produce Traffic Accident Confirmation. If the traffic control department of the public security organ produces the Traffic Accident Confirmation by law, the social insurance administrative department, in the absence of other disputes, often can directly determine whether the injured employee has "primary responsibility" or not based on the division of responsibility in the Traffic Accident Confirmation, and then determine whether the injury suffered by the employee is a work-related injury or not. Nevertheless, real cases are rather complex. The traffic control department of the public security organ often faces difficulties in producing the Traffic Accident Confirmation due to an inability to ascertain the causes and facts of a traffic accident. In such cases, they can only conclude cases with an alternative document -Traffic Accident Certificate. However, such certificates do not present the specific causes of the traffic accident, the faults and responsibilities of the parties involved in the traffic accident, or whether the accident is accidental. Thus social insurance administrative departments cannot directly determine whether the injured employee has "primary responsibility", putting obstacles to the determination of work-related injuries. This paper aims to analyze judicial practice cases to explore the divergence on the burden of proof for "non-primary responsibility" in practice, and to investigate the reasonable allocation of the burden of proof for "non-primary responsibility", thus providing some reference for the judgment of similar cases.