The utility model discloses an intensive condenser pipe of built -in small passageway of triangle -shaped, including outside parent tube, inside core pipe, follow the fin of radially arranging between outside parent tube and the inside core pipe and be 15~30, form 15~30 small passageways of triumph between the fin. The apex angle of the small passageway of triumph is 12~24, and the base angle is 90. Inside core pipe is for solid construction or for the hollow pipeline of both ends jam. Double -phase flow pattern can be regulated and control on the one hand and intraductal heat transfer area is increased to reach the mesh of reinforceing the condensation heat transfer, on the other hand can be applicable to different gravity conditions, including the conventional gravity in ground, little gravity and microgravity environment.