A precision syringe pump employing a syringe comprises a motor, a lead screw and a syringe driving head connected to the lead screw. The syringe comprises a cylinder and a plunger. The motor drives the lead screw to rotate clockwise or counterclockwise to drive the syringe driving head and push the plunger to move within the cylinder. The syringe pump further comprises: a magnetoresistive sensor, at least one permanent magnet and an MCU, the at least one permanent magnet being located on the lead screw and rotating therewith; the magnetoresistive sensor can sense the magnetic field generated by the at least one permanent magnet; the input end of the MCU is connected to the magnetoresistive sensor, and the output end of the MCU is connected to the motor; the MCU receives signals from the magnetoresistive sensor and controls, according to the signal feedback, the direction and velocity of the lead screw rotated by the motor. The precision syringe pump of the present invention is characterized by high sensitivity, high reliability, low power consumption and low cost, and is convenient to use.