Abstract: The experiments of nitrogen．．application and water-fertilizer under mulch cultivation of wheat in arid highland in Changwu，Shaanxi show that the effect of applying nitrogen on yield is obvious，but that of mulch cultivation is not good in special drought year with continual dry in earlier stage．The fertilization is advantageous to improve soil water conditions in 0～100cm of soil horizon and improve water use efficiency．The mulch cultivation plays a role in keeping soil water in earlier stage of wheat growth，and the differences of plantation in mulches and plantation under mulches are not great in soil profile’s moisture．The mulch cultivation can increase soil moisture in upper layer and in plow layer． It is obvious to increase N absorption and improve P and K absorption with nitrogen applying．