Evidence collection activities in administrative cases aim to clarify relevant details and events in the case. Although the activities of collecting and searching for evidence to serve the trial in the process of resolving an administrative case have been specifically regulated on the rights, obligations, order and procedures that the subjects proceed. However, reality shows that Vietnamese law regulations related to collecting and tracing evidence to serve the trial of an administrative case still face many difficulties (Nguyen Thanh Phuong 2021). Specifically, collecting testimonies from the parties involved in the case right at the trial is an important measure. However, the reality of resolving administrative cases in Vietnam shows that in most cases when an administrative case is tried, the defendant is often absent from the hearing, which affects the collection of fees. Collect evidence for court testimony, as well as possibly prolonging the trial of the case. Thereby, through qualitative analysis method, the authors will focus on clarifying issues related to evidence collection methods through taking testimony from the defendant in administrative cases. , at the same time pointing out the inadequacies in the law through the application process in Vietnam. From there, propose solutions to perfect this mechanism in the future in Vietnam.

Key word: evidence, evidence collection, testimony, defendant, administrative case