The invention discloses an electrostatic tail gas purifying and trapping device and method. An oxidization catalytic converter and an electrostatic particulate matter trap are connected into a whole through a flange so as to form the purifying and trapping device of which one end is used as an air inlet and the other end is used as an air outlet; a purifying net is arranged at the air inlet of a shell of the device; and the electrostatic particulate matter trap has the structure that a metal discharging rod is sleeved by a string of tipped metal discs at intervals, and a blade-type metal disc also sleeves among several spaced tipped metal discs. During dust removal, particulate matters are intercepted by the purifying net, tail gases are initially purified and are catalytically oxidized by the oxidization catalytic converter, and the particulate matters are trapped by using the electrostatic particulate matter trap, so that the aim of thoroughly removing dust is achieved.