A method for efficiently purifying and detecting 6-hydroxynobilonine in fresh stems of Dendrobium huoshanense uses a gas chromatography-mass spectrometry (GC-MS) method to detect 6-hydroxynobilonine in Dendrobium huoshanense is, i.e., a to-be-detected solution of 6-hydroxynobilonine is extracted from fresh stems of Dendrobium huoshanense, the extraction method is as follows: freeze-drying, smashing and screening fresh stems of Dendrobium huoshanense to obtain dendrobium dry powder, adding water for performing ultrasonic treatment, and then adding a composite enzyme for enzymolysis to obtain an enzymolysis solution; adding acidity alcohol into the enzymolysis solution, extracting for 1 min under an ultra-high pressure, and then taking filtrate; and concentrating the filtrate in vacuum, then purifying using a mixed-mode cation exchanger (MCX) extraction column, eluting with a methanol-acetonitrile solution, collecting eluent, blowing with nitrogen until no water, and then dissolving with methanol and filtering to obtain the to-be-detected solution.