Abstract: The Chinese population increased rapidly in 18th  and 19th centuries,and reached 430 millions in 1840.Due to this population explosion,peoples were forced to migrate to find new livelihoods.The movements continued  into  the 20th century forming the current patterns of distribution of the Chinese population in China and overseas.The paper also discusses the reasons for the overseas migration,the hard life of overseas Chinese  and the contribution of overseas Chinese to the economic development of their host countries.