The invention relates to a dragon fruit grafting method, which comprises the following steps of (1) selecting a stock; (2) culturing a stock seedling; (3) cutting an aged branch of the dragon fruit into a branch section with length of 6-10cm as a scion, selecting a ridge, cutting a plane with length of 3-5cm along the xylem part of the ridge from the base part of the branch section, longitudinally cutting one part, and cutting the ridge off; (4) transversely cutting one part at the position, 10-20cm away from ground, of the stock, selecting one stock ridge, longitudinally cutting one part along the xylem part of the ridge to form the depth of 3-5cm, parallelly cutting one part to the outside, enabling the width to be the same as the thickness of the scion, transversely cutting one part at the lower surface of the cutting opening, taking the meaty ridge stem out, and forming a groove-shaped union; (5) inserting the scion into the stock union, aligning the xylem parts, fixing, and binding by a plastic tape; (6) coating a plastic bag on a grafting union, so as to complete grafting; (7) after grafting, performing conventional management. The dragon fruit grafting method has the advantages that the operation is convenient, the speed is high, the stress resistance property and suitability of the plant can be improved, the disease and pest resistance capability is improved, the adhering of the scion and the stock is easy, and the survival rate reaches 97%.