The process of hydrolyzing plant protein to prepare cigarette perfume includes the following steps: compounding protein solution in certain concentration with plant protein and water; adding protease and hydrolyzing at proper temperature, pH value and other conditions to controlled hydrolysis degree; deactivating, filtering and decompressing concentration to obtain hydrolyzed protein in certain hydrolysis degree; mixing the hydrolyzed protein with saccharide compounds, adding solvent and catalyst, regulating pH value and heating to reflux react at normal pressure to obtain brown resultant. Compared with available technology, the present invention has the advantages of wide material source and low cost, and the prepared cigarette perfume has multiple aromatic components, scent cooperative with cigarette smell, high solubility and obvious effect of improving quality of cigarette.