Abstract: Zn and P were selected to modified HZSM-5 molecular sieve for further improving the production and fuel quality of refined bio-oil. Analysis methods including XRD, SEM EDS, ICP-AES and BET were applied to characterize the modified HZSM-5 molecular sieves. The influence of physical and chemical properties of refined oil and chemical composition of aqueous phase and the anti-coking ability of modified HZSM-5 with the loading of Zn and P were studied. The results showed that the framework of modified HZSM-5 molecular sieves was not influenced by the modification of Zn and P, which were distributed on the surface of HZSM-5 uniformly. The BET of modified HZSM-5 were declined when Zn loading mass was increased. The physical and chemical properties of refined bio-oil when Zn loading mass was 3% were as follows: oxygen content was 10.67%, high calorific value was 36.76 MJ/kg, pH value was 5.85. Meanwhile, the relative contents of acids, alcohol and ether, aldehyde and ketone in aqueous phase were dropped significantly. Aromatic compounds and aromatic hydrocarbon were increased significantly with the ralative contents were 91.93% and 74.63% respectively. The anti-coking ability of modified HZSM-5 was enhanced with the P loading, which enhanced the stability of HZSM-5. Zn loading promoted the formation of carbenium ion and hydrogen transfer, which improved HZSM-5 molecular sieve aromatization performance.