Abstract: Soil in facility agriculture is hardened because of over cultivation and lack of natural arrangement，tilling depth of traditional rotary tillage can only reach to 10～15 cm，it formed a thick plow pan under 15 cm，the plow pan reduces soil permeability and storage capacity.Concerning this issue，a deep cultivator was designed，its tilling depth could reach to 30 cm.Its working quality could meet rotary operating standards.Power selection，design and array of tiller blade were introduced in detail.