Beihe dialect is a distinctive dialect. It is a mixture ZhongYuan and Xinan dialects. The paper attempts to look into its social, historians, cultural and geographical causes. It is composed of four ports:Part one,Because Baihe's original inhabitants were connected with chuan and chu in the remote antiquity, Bathe's native dialect was a hybridism. Part two, the earliest historical records of the migration into Baihe proves a powerful backing for the cause of formation. Part three, the frequent changeful administrative division of Baihe is an important cause. Part four,the particular traffic and geography is the moot important cause for the hybridism.