The invention provides an expandable dotting marking method and device. The dotting marking device comprises a fixed main body, a driving actuating mechanism and a moving main body, wherein the driving actuating mechanism is arranged on the fixed main body; the moving main body is in driving connection with the driving actuating mechanism and is provided with a positioner which can be fixedly provided with a marking pen in a sleeving manner; the moving main body is driven by the driving actuating mechanism to vertically move in a reciprocating manner. The expandable dotting marking method is convenient to operate, and can be assembled along with detecting equipment; the expandable dotting marking device is reasonable in structural design, is applicable to various marking pens, is simple in structure and high in stability, and is suitable for marking pens with various specifications and models; in addition, the expandable dotting marking device further has an ink evaporation protecting function of the marking pens, the service lives of the marking pens are prolonged, and the circumstances that detection workload is increased due to failed marking are reduced.