Liquid smoke processed by thermal pyrolysis at 450 ℃ under nitrogen protection was prepared as a flavoring agent from peach wood. Its effect on the flavor characteristics and consumer acceptability of sirloin steak was investigated. Various liquid smoke concentrations and marination times were applied to the smoking process. Sensory descriptors were summarized by focus group tests and illustrated by a word cloud method. Flavor evaluation was carried out using check-all-that-apply questions and principal component analysis (PCA). Results showed that the liquid smoke significantly improved the sensory descriptors of steak, including mild smokey, barbequed, cooked beef-like and meaty flavors, dark color, chewy and juicy texture. Correlation analysis showed that both the overall preference and odor preference were positively correlated with the flavor preference. Chemical analysis showed that the liquid smoke at low concentrations used in this study did not have significant effect on the moisture content, fat content or pH of steak.