This text passes the problem that the E-mail formation and its technique characteristic, the E-mail evidence certificate dint appear and resolve path etc.

To compare the mainland legal system to British and American legal system expert testimony evidence ability and the certificate strength,it analyzes conclusion of legal appraisal ability and the certificate strength in our country.

The evidence got by secret monitor has the nature of legal principles of evidence ability.

When examine the evidence ability,should take "No objection can be taken,there is a limited objection to the admissibility of"as standard.

The key problem is how to grasp its effect of evidence exactly.

The effect of evidence shows that the expertise is not the unique evidence of the court judging whether the medical institute should be responsible, nor is it prior to other proofs.

The procedure mode put an impact on evidence capacity by undercover investigation.

Whether the illegal evidence has the evidence capacity and the Exclusionary Rule of Illegal Obtained Evidence should be set up or not, which mainly reflect clash and coordination of the value goals between punishing criminal and defending human rights.