As a new kind of grain crop ,the introduction and extensive growth of corn in Qinba mountainous areas in mid-Qing dynasty,has largely changed the local original mode of production and lifestyle. With the advantages of high adaptability to the environment,high yield and wide use,more and more immigrants were attracted to plant corn,which made local people’s livelihood obviously improve,promoted the development of this area and broke the closed state of this area. But the great pressure of grain caused by excessive population growth has led to both the destruction of Qinba Mountain reclamation and the serious ecological problems.