The invention relates to a bipolar transistor and a manufacturing method thereof. The method for manufacturing the bipolar transistor comprises the following steps of: providing a semiconductor substrate; performing ion implantation on the first semiconductor material layer; etching the first semiconductor material layer and an embedding dielectric layer to form a semiconductor material pillar and a dielectric support pillar; removing the middle segment of the dielectric support pillar; depositing a metal layer on the substrate to at least embed the semiconductor material pillar; etching the metal layer to form a metal base electrode; performing vertical light doping on the exposed part at both ends of the semiconductor material pillar; and performing inclined heavy doping on the exposed part of the semiconductor material pillar. The invention ensures that a heavily doped emission region contacted with the base region and a lightly doped buffer region between the base region and the heavily doped collector region can be formed in one step by firstly performing vertical light doping and then performing inclined heavy doping on the emission region and the collector region so as to control puncture voltage between the emission region and the collector region by controlling the heavy doping angle.