The establishment of the supervisory committee has brought some new changes. it absorbed the anti-corruption and anti malfeasance crimes of the procuratorate into it, breaking the situation of the Procuratorate's self investigation and private prosecution of the duty crimes in the past. It has changed the situation of "horizontal separation and vertical integration", which plays an important role in the construction of anticorruption legal system and is an important progress in the construction of anticorruption legal system. "Investigation" is not mentioned in the full text of the supervision law, but the duties performed by the investigators of the supervision commission are the same as those of investigation, so it is necessary to introduce the right of lawyer's assistance. At the same time, we should establish a professional team of supplementary investigation, which is mainly composed of Procuratorate's own investigation, and establish the two-step strategy of supplementary investigation after the examination of qualification elements and substance elements, so as to connect the evidence obtained in the investigation of duty crimes. In this way, the procedural rights of the investigated can be guaranteed without affecting the handling of the case, which is also conducive to the handling of the case.