In view of the fact that formaldehyde is very harmful air pollutants for human body

it is necessary to monitor whether the indoor formaldehyde concentration is in excess of the standard in real-time

an indoor formaldehyde monitor

which is cheap

easy to install

operate

and move

and has reliable test results is in urgent need of development. The designed formaldehyde monitoring system uses STC12 C5 A60 S2 microcontroller unit（ MCU） as the main control chip of the hardware circuit and the CJMCU—1100 sensor as the data acquisition circuit. The upper personal computer（ PC） panel is designed by using Lab VIEW graphic programming method. The current formaldehyde concentration is represented by the pointer and the curve. The color indicator lamp is used to alarm the concentration exceeding the standard. The test results show that the accuracy class of the monitoring system is 0. 5

the resolution is 0. 05

and the real-time monitoring of formaldehyde concentration can be easily completed.