To understand the codoping effects on the photocatalytic activities of Zn2GeO4 with wide band gap,we make a thorough investigation on the electronic structure and optical properties of N/F-codoped Zn2GeO4 by performing the first-principles calculations.The results show that the doping of N can reduce the band gap with a deep accepter level closing to the bottom of conductor band which may be a recombination center.There are more impurity levels in the forbidden band that have overlaps with Fermi level,in N/F-codoped Zn2GeO4,which could be springboard for the electrons transition.The N and F coincorporation generate lighter effective mass for charger carries resulting higher transition rate,moreover,the absorption length expand to visible-light region.The N related defects acceptor can be passivated by the electron transfer from F.As a photocatalyst,the N/F-codoped system should manifest high energy conversion efficiency under visible light irradiation.