A mini lead screw pump (2) monitors the rotation of a lead screw (22) by using a magnetoresistive sensor (28) and an MCU (50), and uses feedback to control the rotation direction and speed of the lead screw (22) through a motor controller (48) so as to control the speed of infusion to a patient. Furthermore, this mini lead screw pump (2) can control the infusion speed of insulin according to the patient's blood sugar concentration monitored by CGM (45). This mini lead screw pump (2) has several advantages, comprising high sensitivity, high reliability, low power consumption, low cost, and ease of use.