The invention aims at providing a three-phase three-wire series type dynamic voltage compensation device so that problems of large circuit, low work reliability, high cost, and difficult promotion ofthe existing series type dynamic voltage compensation device can be solved. The three-phase three-wire series type dynamic voltage compensation device is composed of a voltage amplitude detection circuit, a differential voltage and switching time change-over circuit, and a voltage amplitude conditioning circuit. Compared with the prior art, the three-phase three-wire series type dynamic voltage compensation device has the following advantages: the structure is simple; the response is fast; the cost is low; the compensation device is convenient to promote and apply; a dynamic voltage amplitudeunder-adjustment or over-adjustment phenomenon is avoided; and the high reliability of the dynamic voltage amplitude conditioning work is ensured.