The invention relates to a shell and tube heat exchanger used as a coolant mechanism. The shell and tube heat exchanger comprises a plate-fin arranged inside or outside a heat exchanger tube, and at least one heat exchanger tube internally provided with the plate-fin. Through the heat exchanger has simple structure and easy manufacture, the heat exchanger can still limberly process fluid bodies with different shapes, promote the effective heat exchanging action of the fluid bodies, obtain good cooling efficiency, and can process a plurality of fluid bodies. The plate-fin that the invention relates to is the plate-fin for stirring liquid; the plate-fin is arranged inside or outside the heat exchanger tube to lead the fluid bodies which is composed of cooled medium or refrigeration medium to flow inside or outside the heat exchanger tube, thus impingiment flow or vortex flow with stirring action are generated; the plate-fin is arranged inside or outside the heat exchanger tube, and thus the blade edges of the plate-fin are butted and jointed up and down to enable the blade edges opposite to each other, and each butted and jointed blade edges are crossed with each other. The invention also relates to a method for manufacturing the plate-fin as well as the heat exchanger tube internally provided with the plate-fin, and the heat exchanger or an EGR gas cooling device provided with at least one heat exchanger tube.