Abstract: Loess Plateau of northwest,illumination is abundant.Rain and heat is in a period.Microclimate of farmland have the obvious effect while a technology of plastic sheet mulching strip land with rainfed was carried out.The ground temperature increase 2-5℃,water saving 30-40mm.It is reached 70% or so the regulation of water with each other.Heat use efficiency is 0.99,precipitation is 15.15kg/(mm·hm2) the climate produce potential exponent is 0.49.The increase produce have the obvious effect changing one into two cultivation a year.Total output attained 8250-9000kg/hm2,increased yield over 45% ocomparision with the monocultivation.