The utility model discloses an outdoor-smog monitoring apparatus which is characterized in that the apparatus comprises a smog sensor, a wind speed sensor, a humiture sensor, a signal conditioning circuit, a single-chip microcomputer, an input apparatus, an alarm and an LED display, wherein the smog sensor, the wind speed sensor and the humiture sensor are connected with an input terminal of the signal conditioning circuit in parallel. An output terminal of the signal conditioning circuit is connected with an input terminal of the single-chip microcomputer. The other input terminal of the single-chip microcomputer is connected with the input apparatus. One output terminal of the single-chip microcomputer is connected with the alarm and the other output terminal of the single-chip microcomputer is connected with the LED display.