In this paper， apple， pomegranate and brown plum were used as raw materials to prepare composite juice. Sensory evaluation of different proportions of composite juice was carried out to determine the best ratio， and the effects of high hydrostatic pressure （HHP） treatment parameters （treatment pressure， holding time） on the microbes and quality of composite juice were studied. The optimal compounding ratio of the composite juice was mapple juice ∶ mpomegranate juice ∶ mbrown plum pulp =16 ∶ 3 ∶ 1. After 400 MPa/5 min， 500 MPa/1 min， 500 MPa/3 min and 500 MPa/5 min treatment， the counts of total aerobic bacteria and yeasts and molds met the requirements of ‘Chinese National standards for food safety Beverages GB 7101-2015’. Compared with the untreated group， HHP treatment and heat treatment had no significant effects on the pH， total soluble solids （TSS） and color of the sample. The total phenol and ascorbic acid content of HHP-treated samples were not significantly different from heat-treated ones， but the DPPH removal ability and ferric ion reducing antioxidant power （FRAP） of the HHP-treated samples were significantly higher than heat-treated ones. The DPPH removal ability of HHP-treated samples was 8.57%-18.10% higher than heat-treated ones， and the FRAP was 11.50%-24.78% higher. HHP treatment increased the viscosity of the samples， while heat treatment reduced the viscosity of the samples. Both HHP treatment and heat treatment changed the volatile aroma components of the samples， but the content of the retort component after heat treatment increased more. The passivation effect of HHP treatment on endogenous enzyme activity was worse than that of heat treatment， and the residual enzyme activity of polyphenol oxidase （PPO）， peroxidase （POD） and lipoxygenase （LOX） was between 65.13%-76.97%， 75.00%-85.42% and 75.00%-85.00% in HHP-treated samples， respectively， while 15.35%， 7.29% and 45.00% in heat-treated ones.