The mode of adjudication based on files causes verification by overlapping written evidence in criminal trial . Verification has the function to find out the truth of a case . In the meanwhile,it has the effect of increasing errors on adjudication . As verification by overlapping written evidence infracts the rule which all evidence of a case shall only be overlapped after each piece of evidence has been examined independently,the effect of increasing errors on adjudication is difficult toavoid .Verification byoverlapping written evidencecan also bringabout theeffect of reverse encouragement that investigation organs are promptedor encouraged to makefalsefiles or records .At present,it is impossible to abandon verification by overlapping written evidence in a short period . The ways to decrease these negative effects lie in raising judges'consciousness and ability to examine each piece of evidence singly,and establishing the system of testifying in court on doubtful points,the priority of examining testimony in court,and the system of discovery of evidence before trial.