Glycosylation is an essential post-translational modification. Over 50% of proteins in the human body undergo glycosylation, which can influence their biological functions and participate in various biological processes. Abnormal glycosylation occurs in a range of physiological and pathological processes, such as cancer, inflammation, or metabolic diseases, making the detection of glycosylation essential. Classical methods for detecting glycosylation, like flow cytometry and mass spectrometry, often struggle with trace-level glycosylation signals. This study reports a DNA amplification-based method for glycan detection. Lectins that recognize and bind certain glycosylations are labeled with single-stranded DNA (ssDNA). The specific binding between lectins and glycans convert the "glycan signal" into a "nucleic acid signal". Using the ssDNA as a template for PCR amplification enables the detection of trace glycosylation signals, offering a new perspective for glycobiology research and the discovery of clinical glycomarker.