The invention provides a pig-keeping system capable of intelligently monitoring environments, and a monitoring method thereof. The pig-keeping system comprises a microcontroller in connection with a clock module; the microcontroller is in connection with temperature and humidity sensors for monitoring pig house environments, and ammonia gas, hydrogen sulfide and concentration detection sensors; the microcontroller is also in connection with a drawing fan, a purge valve, an infrared lamp, and forage feed and drinking-water valve control relays. Each relay is in connection with associated facilities. The monitoring method comprises: the microcontroller storing ammonia gas, hydrogen sulfide and carbon dioxide content set values, temperature and humidity set values, cleaning time, and feeding and water supply time; and starting associated relays to perform cleaning, exhausting, heating, humidification, food and water supply, etc. according to set parameters. The pig-keeping system can monitor independently, operate efficiently, save manpower and resources, guarantee sanitation, reduce costs, and improve farming efficiency; a plurality of systems are in wireless connection with a host computer to accept technical guidance and to boost a management level; set parameters of each system can be automatically adjusted, or controlled by the host computer.