证人出庭作证,是现代庭审制度的基本要求,警察作为行使侦查权的国家机关工作人员,作为证人出庭作证有其法理、法律依据和诉讼价值。警察出庭作证,并接受被告人及其辩护律师的质询,这样既能支持检察官对犯罪嫌疑人的公诉,又能有助于排除非法证据,同时还可以促进警察在侦查工作中注意证据的收集和保证证据链的有效和完整。 Witness to testify in court is the basic requirement of the modern trial system. The police, as the staff of state organs exercising the investigative powers, has its legal basis, legal basis and litigation value as a witness to testify in court. The police testified in court and accepted the defendants’ and their defense lawyers’ questions so as to support prosecutors’ prosecutions of criminal suspects and help to eliminate illegal evidences. At the same time, they can also promote the police’s attention in the investigation of the collection of evidence And ensure that the chain of evidence is valid and complete.