The Nan-ao Atayal, an eastern branch of the Atayal, with the population of about four thousands inhabit the southeastern part of the Ilan prefecture. Genealogically the Nan-ao Atayal consist of the members of three sub-tribes of the Atayal, namely: seqoleq, tseʔole and sedeq. Among these, four groups can be further distinguished. These groups are kena-xaqul, mebeala, manebo and tausa. The original settlements of the Nan-ao Atayal were in mountains of more than one thousand meters along the upper and middle valleys of the Ho-ping River. There were 13 original villages or kelaŋ as follows: piəxau, təlaŋan, tepijaxan, gogot, rekinos, kiŋijan, babo-lelao, regeax, xaga-paris, tubulag, mojau, babo-kaikai and lejoxen.

　　Beginning from the Japanese occupation of the island until quite recently, there were several movements and resettlements, during which the original villages were scattered and recombined into new villages in the delta region of the Nan-ao River. Nowadays, there are seven villages under the present administration, namely: Nan-ao, Tung-ao, Wu-ta, Chin-yue, Pi-hau, Ao-hua and Chin-yang. The first six are recently established villages, only the last one remains at the original site. The move from the original habitat to the new locality means the change of environment from the mountainous area into the plain and from a relatively isolated place into a spot where contact with outsiders became more frequent.

　　Actually the delta region of the Nan-ao River which the Atayal now inhabit is also an aged outpost of the Chinese. The first Chinese pioneers known to enter this plain were soldiers engaged in construction of the Su-ao Hualien trail in the middle of the 19th century. The present Chinese settlement was started later at the beginning of this century. During this stage, the contact between Atayal and Chinese was rather accidentally and indirectly. According to the present administrative system, the Nan-ao plain is actually divided by the Su-ao Hualien Highway into two different counties; the east side of the highway belongs to Su-ao county and the west side is Nan-ao county—the reservation for the Nan-ao Atayal. Therefore, in this proximity and under the present government policy, the Atayal frequently communicate with Chinese in every phases of life.

　　Besides the population of the Su-ao county which is exclusively Chinese, in the county of Nan-ao there are also some Chinese which consist mostly of governmental workers and servicemen. Among the population of 4,348 in Nan-ao county at the time of our investigation more than 90% were Atayal tribesmen. The demographical figures of the Nan-ao Atayal can be seen from the data of Nan-ao and Chin-yang villages which were chosen for intensive study. The following chart shows the population, household number and sex ratio of these two villages now under different setting and different economical conditions.

As for the distribution of age groups, both Nan-ao and Chin-yang belong to the category of progress type according to Süudbarg's Classification.

　　In the following paragraphs we shall summarize our findings on socialization process, social groupings, and supernatural beliefs and practices respectively. We shall describe the traditional Atayal culture in the sense of the ethnolgical present. Their changes in response to the impact of modern culture will be dealt with in the last paragraph.