A brake lever, comprising a protective casing, a fixing assembly cooperatively fixing the protective casing, a connecting member for connecting a hand brake cable, and a hand brake assembly, wherein the hand brake assembly comprises a main arm with one end rotatably connected to the protective casing and the other end rotatably connected to a handle; the main arm is driven to rotate by applying a force to the handle, the connecting member is driven by a transmission member to move in the direction of tightening the hand brake cable when the main arm rotates; the handle is provided with an auxiliary supporting arm, and two ends of the auxiliary supporting arm are rotatably connected to the protective casing and the handle, respectively; the transmission member comprises a strip-shaped tooth formed on a side surface of the connecting member and a circular arc shaped rack located on the main arm, the strip-shaped tooth is meshed with the circular arc shaped rack, and a circle center of the circular arc shaped rack coincides with the rotation center lines of the main arm and the protective casing; the main arm and the auxiliary supporting arm are arranged parallel to each other, a first hinged point between the main arm and the protective casing, a second hinged point between the main arm and handle, a third hinged point between the auxiliary supporting arm and the protective casing, and a fourth hinged point between the auxiliary supporting arm and the handle are located at four points of a parallelogram respectively; the handle comprises a gripping section, and the gripping section is parallel to a handlebar during rotation of the main arm and the auxiliary supporting arm; the third hinged point between the auxiliary supporting arm and the protective casing is located at the first hinged point between the main arm and the protective casing towards a rotation direction of the main arm during braking, and the third hinged point between the auxiliary supporting arm and the protective casing is closer to the handlebar than the first hinged point between the main arm and the protective casing; the protective casing is provided with a square hole penetrating through two ends of the protective casing; the connecting member comprises a column passing through the square hole; the column is formed with a circular groove having a diameter slightly larger than a diameter of a hammer head of the hand brake cable on a side of the column facing side walls of the square hole, a first side groove communicating with the circular groove is formed on the side of the column with the circular groove, a side of the first side groove away from the circular groove penetrates through a side surface of the column, a second side groove is formed on one side of the column facing a port of the square hole, and the second side groove extends from the middle of the column to a position penetrating through a same side of the column. the transmission member comprises a strip-shaped tooth formed on a side surface of the connecting member and a circular arc shaped rack located on the main arm, the strip-shaped tooth is meshed with the circular arc shaped rack, and a circle center of the circular arc shaped rack coincides with the rotation center lines of the main arm and the protective casing; the main arm and the auxiliary supporting arm are arranged parallel to each other, a first hinged point between the main arm and the protective casing, a second hinged point between the main arm and handle, a third hinged point between the auxiliary supporting arm and the protective casing, and a fourth hinged point between the auxiliary supporting arm and the handle are located at four points of a parallelogram respectively; the handle comprises a gripping section, and the gripping section is parallel to a handlebar during rotation of the main arm and the auxiliary supporting arm; the third hinged point between the auxiliary supporting arm and the protective casing is located at the first hinged point between the main arm and the protective casing towards a rotation direction of the main arm during braking, and the third hinged point between the auxiliary supporting arm and the protective casing is closer to the handlebar than the first hinged point between the main arm and the protective casing; the protective casing is provided with a square hole penetrating through two ends of the protective casing; the connecting member comprises a column passing through the square hole; the column is formed with a circular groove having a diameter slightly larger than a diameter of a hammer head of the hand brake cable on a side of the column facing side walls of the square hole, a first side groove communicating with the circular groove is formed on the side of the column with the circular groove, a side of the first side groove away from the circular groove penetrates through a side surface of the column, a second side groove is formed on one side of the column facing a port of the square hole, and the second side groove extends from the middle of the column to a position penetrating through a same side of the column.