In China, the status in quo of witness presenting at court has long been associated with a successful reform of court trial.

On the professional characteristics of criminal investigators;

Discussion on Unhealthy Work s Psychology with the Investigator;

Study on Some Questions about the Witness of the Investigators in the Court;

This article offers some feasible proposals to perfect witness system,such as enlarging the scope of witness,changing the authority of investigators,giving economic compensation,etcetl.

Facing the new situation after China s entry of WTO,investigators should have a perfect mastery of political quality,legal sense,style of discipline and high efficiency of work.

Evidences could not be object to testify according to semantical and logical meaning,based on which with analyzing the appearance in court,a conclusion may be drew that the investigation personnel has not boren testimony in court but asisted with public prosecution.