Zinc selenide (ZnSe) is a direct band gap semiconductor material with a band gap of 2.7 eV at room temperature, and is a very promising blue light emitting material. However, the ZnSe nanomaterials grown by the usual Au-catalyzed chemical vapor deposition (CVD) method are prone to cause defects in the material, and its luminescence spectra generally have strong yellow light emission, which seriously affects its application in blue light devices. The paper proposes a simple method for preparing blue light-emitting ZnSe nanowires. Adding a small amount of SnO2 to the source material ZnSe powder, when using the CVD method to grow ZnSe nanomaterials, can obtain ZnSe nanomaterials with only band edge blue emission. SnO2 can not only act as a catalyst, promote the growth of ZnSe nanowires and nanoribbons, reduce the growth temperature of nanomaterials, but also avoid the occurrence of deep level defects in ZnSe nanomaterials, and obtain pure blue light emitting ZnSe nanowires. The emission peak of the nanowire grown by this method can be shifted from 460 to 500 nm. By precisely regulating the growth of the nanowire, it can make it emit light to cover the entire blue region, which can promote the application of inorganic semiconductor nanomaterials in the field of lighting and display.