The invention discloses a three-dimensional ultrasound biomicroscope for cylinder scanning. In the three-dimensional ultrasound biomicroscope, a motor 1, a coupling sheet 1, a photoelectric encoder 1 and a motor fixing sleeve are connected sequentially; one end of a motor 2 passes through an aperture on the base of the motor fixing sleeve and is fixedly connected with a coupling sheet 2; a supporting frame is fixed on the base of the motor fixing sleeve; a photoelectric encoder 2 is arranged between the base of the motor fixing sleeve and the coupling sheet 2; both ends of a transmission bar are connected with an off-centre position of the coupling sheet 2 and a transmission frame respectively; a guide rail is in a linear type and passes through a slot of the transmission frame, and both ends of the guide rail are fixed on the supporting frame; a sliding block is arranged below the guide rail and is fixed on the transmission frame; one end of a probe is connected with the transmissionframe, and the other end of the probe is provided with a sensor; the sensor is connected with a control line board; the photoelectric encoder 1 and the photoelectric encoder 2 are connected with the control line board; and the control line board is connected with a programming controller. The three-dimensional ultrasound biomicroscope has a simple structure, a controllable scanning range and highscanning efficiency and is convenient to operate and simple in data processing.