The invention relates to an extraction method of high-purity coptis total alkaloid, which comprises the following steps: preparing a raw material (coptis or coptis fibril or coptis ash), pulverizing (not required if the raw material is coptis fibril or coptis ash), immersing in 0.1-5% sulfuric acid, heating and extracting four times, filtering, neutralizing with calcium oxide (or calcium hydroxide), filtering, washing the precipitate, preconcentrating, regulating the acid, precipitating with sodium chloride, filtering, recovering alkaloid from the mother liquor, and drying the precipitate to obtain the coptis total alkaloid product. The main active components of the product are coptis effective components, such as berberine, coptisine, palmatine, epiberberine, jateorhizine and the like; the coptis total alkaloid content is more than 50%; and the berberine content is more than 25%. The product provided by the invention has favorable actions of lowering blood sugar and blood fat, losing weight and the like, and is an ideal raw material for treating diabetes and cardiovascular diseases.