The invention discloses an Internet of Things greenhouse agricultural growth monitoring system and relates to an agricultural growth monitoring system. The Internet of Things greenhouse agricultural growth monitoring system comprises a plant ecology sensing system, a meteorological environment sensing system, and an equipment control system. The plant ecology sensing system and the meteorological environment sensing system transmits acquired data to a host computer. The host computer controls the start and the stop of the equipment control system. The plant ecology sensing system comprises a plant stem flow gauge, a tree radial growth monitor, a chlorophyll content measuring sensor, a leaf thickness sensor, and a fruit expansion sensor. The meteorological environment sensing system comprises an air temperature sensor, an air humidity sensor, a soil temperature sensor, a soil humidity sensor, a carbon dioxide sensor, an in-greenhouse illumination sensor, an out-greenhouse illumination sensor, an out-greenhouse rainfall sensor, and an out-greenhouse wind direction and wind speed sensor. The Internet of Things greenhouse agricultural growth monitoring system guarantees optimum plant growth environment and state, saves production cost, and reduce production energy consumption.