A large single crystal of a nonlinear optical material Bi2ZnOB2O6 (BZB) has been grown by the Czochralski method. l'he experiments of linear and nonlinear optical property were performed. On the basis of the density function theory (DFT), the first-principles calculations have been employed to study the structural and electronic properties of BZB successfully. The calculated results are essentially consistent with the corresponding experimental results. In addition, to gain further insight into the structure-property relationship, a real-space atom-cutting method was adopted to analyze the origin of the nonlinear optical response of BZB for the first time. The results indicate that the contributions nf the (BiO6)(9-) and (B2O5)(4-) groups are dominant in the BZB crystal for producing large microscopic second-order susceptibilities.