The invention relates to the technical field of environmental protection detection, and discloses an indoor and outdoor decoration engineering environmental protection monitoring device which comprises an indoor decoration pollution gas automatic monitoring system. The indoor decoration pollution gas automatic monitoring system comprises a processor, a GSM module, a power supply module, a sensingmodule, a Bluetooth module, a WiFi module, a liquid crystal display, an intelligent air conditioner, a keyboard and an audible and visual alarm. The processor is electrically connected with the GSM module, the power supply module, the sensing module, the Bluetooth module, the WiFi module, the liquid crystal display, the intelligent air conditioner, the keyboard and the audible and visual alarm. The Bluetooth module is in Bluetooth wireless connection with a smart phone; and the WiFi module is wirelessly connected with a computer client. Real-time monitoring of an indoor pollution gas is achieved, ventilation and temperature and humidity adjustment are performed indoors in time, safety of new house occupancy is improved, a user can be reminded that the indoor pollution gas exceeds a standard in time, ventilation is performed in time, indoor environment quality is improved, and harm to a human body is reduced.