The invention relates to a counting pyroelectric infrared sensor-based counter formed by five parts. According to the system, a low-cost single-chip microcomputer is used as a controller and is responsible for instruction controlling of the whole system. And with cooperation of a key, a display, a buzzer, and a sensor, functions of system working mode setting, system working state prompting, and people counting statistics and displaying and the like are completed. The counting infrared sensor that is a pyroelectric sensor especially for counting serves as the core of the whole system. The main distinction between the counting infrared sensor and the common infrared sensor is that the counting infrared sensor has the small view field that is presented to be a line basically, so that the sensor can be used for counting based on the characteristic.