In this present study， enzymatic hydrolysis and Maillard thermal reaction by adding exogenous sugars were employed to produce Maillard reaction products(MRPs) for flavor improvement of enzymatic hydrolyzed juice by-product derived from cooked potatoes prepared by frozen-thawing process. Single-factor experiments combined with orthogonal experiments were employed to optimize the enzymolysis liquid reaction conditions. Changes of volatile favor compounds， free amino acids and antioxidant activity of Maillard treated juice were analyzed. Results showed that the optimal parameters for Maillard reaction were: 3.0% mixed xylose and fructose with a mass ratio of 1∶3， initial pH 6.0， and reaction at 110 ℃ for 50 min. The types of volatile substances in MRPs were increased significantly， the content of hydrocarbons and alcohols were decreased or even disappeared. Moreover， furfural， dimethyl butyraldehyde， benzaldehyde， phenylacetaldehyde， pyrazine， pyridine characterized nutty and barbecue aroma formed， and therefore contributed to the flavor improvement of potato juice. In addition， the total content of free amino acids was decreased by 22.52%， the umami acids and sweet amino acids increased by 2.88% and 0.85%， the bitter amino acids was decreased by 3.72%. In terms of antioxidant activity in vitro， ferric ion reducing antioxidant power increased by 3.35 folds， the DPPH free scavenging activity increased by 55.82%， and the ABTS free radical scavenging rate increased by 33.12%. Overall， the application of Maillard reaction by adding exogenous xylose and fructose can be used a promising strategy for improving flavor and antioxidant activity of the enzymatic hydrolyzed potato juice by-product.