Pleasant aroma of freshly squeezed orange juice is a complex mixture of volatile compounds.Fresh juice is unstable and thermal processing can reduce enzyme and microbial activity.However,thermal processing will reduce concentrations of some juice volatiles and induce off-flavors or their precursors.The chemicals are produced in the processing such as 4-vinylguaiacol,p-cymene,and carvone.Butane-2,3-dione,guaiacol and 2,6-dichlorophenol are microbial contaminants.The paper briefly introduced the different active aroma compounds of orange juice,especially emphasized the aroma compounds changes in the processing,packaging,storage,and microbial contamination.The problems during the research and possible researching fields are also proposed.