Abstract: Since the transit metals, such as Fe, Cr and Ni, contained in some kinds of mixed HLW, can likely to form crystal, increase the melt viscosity, destroy the chemical durability and block the discharge port. The results obtained from investigating four glass waste-forms, including the alkali borosilicate glass matrix and alkali borosilicate glass matrix doped with 5.6%ZnO and 1.75%CaO in base matrixes, immobilizing the simulated mixed HLW with 15% and 20% waste loadings aiming to determinate the effect of ZnO on the alkali borosilicate glass chemical durability with waste loading increasing, were presented in this paper. Glass samples were characterized with XRD and Raman spectroscopy. The chemical durability was investigated using the standard protocols PCT and VHT. The XRD analysis results show that spinel crystal appears and grows in glass samples at the waste loading in 20% without ZnO addition and waste loading in 15% and 20% added ZnO. The Raman spectroscopy analysis results indicate that ZnO and CaO can enhance the glass network connective, and the chemical durability test results display that the addition of ZnO and CaO can improve the short term chemical durability of the glass samples, except Zn20 obtained the lower value in VHT result, which is caused by the higher crystal ratio and lower fracture toughness.