Dendrobium, an important medicinal plant, is a source of widely used herbal medicine to nourish the stomach and treat throat inflammation. The present study is aimed at distinguishing and evaluating three major Dendrobium species by comparing physiochemical characteristics and understanding differences between different growth years in the Ta-pieh Mountains. Polysaccharides and total alkaloids of Dendrobium were determined, and the amino acids and trace elements were determined by UPLC (Ultra High-Performance Liquid Chromatography) and ICP-MS (Inductively coupled plasma mass spectrometry). It can be seen from the results that the polysaccharide content of these three kinds of Dendrobium in different growth years ranges from 249.31 mg·g-1 to 547.66 mg·g-1, and the highest content is in the 3-year-old Dendrobium huoshanense. The total alkaloid content ranges from 0.21 mg·g-1 to 0.54 mg·g-1, and the highest content is also the 3-year-old Dendrobium huoshanense. We determined the amino acid content of these three Dendrobium in different growth years, and we can see that each of the three kinds of Dendrobium contain seven kinds of amino acids required by the human body. We conducted a safety evaluation of the essential trace elements of Dendrobium, and the results showed that the dosage of 12g·d-1 Dendrobium prescribed in China Pharmacopoeia is in accordance with the recommended daily intake of trace elements recommended by the Food and Drug Administration of the United States, and will not cause trace element poisoning. Linear discriminant analysis was carried out on the basis of amino acids and trace elements and confirmed the applicability of multi-elemental analysis for identifying different Dendrobium species.