Abstract: Legislation modification and litigation system reform have gradually strengthened the protection of lawyers right in practice. In order to realize the dynamic balance between the right of investigation and the defense of duty crime， it is necessary to reexamine and rationalize the relationship of such right and defense for duty crime to transform the traditional “partial confrontation， one-way control” into the favorable interaction of “balance+collaboration”. Balance， as the foundation， includes confrontation and restriction， and cooperation， as the complement， includes supervision and promotion. It is of great necessity to establish a new “balance+collaboration” relationship in the following aspects: a mutual communication and supervision mechanism should be established for the investigator and the defense attorney; the lawyers right of meeting timely should be ensured; the lawyers right to relief should be protected in effect; the limited discovery of investigation procedure should be made; and the investigation bargaining system should be attempted.

Key words: duty crime, investigation, relationship of investigation and defense