Objective To establish a specific identification method for Ganoderma lucidum extract, and achieve the synchronous determination of a variety of monosaccharides. Methods The analysis of monosaccharide composition in Ganoderma lucidum extracts was conducted using a pre-column derivatization reversed-phase liquid chromatography method. A quantitative analysis of multi-components by single-marker method was established to determine the monosaccharide content in Ganoderma lucidum extracts. Results Ganoderma lucidum extract from 3 manufacturers contained mannose, glucose and galactose, but the proportion of monosaccharides in 4 batches was significantly different. The content of mannose, glucose and galactose could be determined by one test and multiple evaluation method at the same time. The relative deviation from external standard method was less than 5%, and there was no significant difference, which was feasible. Conclusion This study analyzes the monosaccharide composition and monosaccharide ratio in Ganoderma lucidum extract, which can serve as an auxiliary means for identifying the quality of Ganoderma lucidum polysaccharides in Ganoderma lucidum extract. It provides a reference for enterprises to monitor the quality of extracts.