The invention discloses a method for detecting the polysaccharide content of a ganoderma lucidum extract through near-infrared spectroscopy. The method includes the following steps that firstly, a ganoderma lucidum extract sample is selected; secondly, near-infrared spectral acquisition is conducted; thirdly, a wave band area is selected; fourthly, spectrum data are preprocessed; fifthly, a prediction and correction model is optimized; sixthly, a PLS prediction and correction model is built; seventhly, the models are verified. By means of the method, the polysaccharide content of the ganoderma lucidum extract can be quickly and quantitatively detected, and detection time of each sample is within one minute. Under the significance level of 0.05, a prediction value and an actual measurement value almost have no significant difference, detection is accurate and reliable, the method can be directly applied to online detection of the polysaccharide content of the ganoderma lucidum extract, and the method has wide application and development prospects.