The effects of different heat treating (water bathing 1; 1.5; 2 min; steam treating 1; 1.5; 2 min) on the enzyme deactivation and main quality of lemon were studied herein. The results showed that longer heat treatment time gave better peroxidase passivation effect in lemon; but could cause greater impact on lemon quality. With the increase of blanching time; and the color change was more obvious; the steam treatment slightly increased the contents of sugar; malondialdehyde; ascorbic acid and phenolic. While in the boiling water; their contents decreased due to their water solubility. After blanching; volatile aroma compounds increased significantly; especially aldehydes and olefins.