The invention provides a soil moisture content monitoring instrument based on an embedded system, which comprises an AVR series Megal 16 singlechip, an arch electrode couple and a soil moisture sensor comprising signal conditioning circuits; a Samsung ARM7 S3C44BOX chip, peripheral circuits and an epigynous machine controlling system which comprises a liquid crystal monitor with a touch screen; a wireless communication module; and a power supplying system which comprises a solar panel and a storage battery. The singlechip gathers directly the soil electrical conductivity data which are measured by the soil moisture sensor and transferred into soil moisture data inside the singlechip; at the same time, through the wireless communication module and according to the requirements of the epigynous machine, the measured data are transmitted in real time or fixed time, or the controlling orders of the epigynous machine are received.