Absence of the allocation of oases ecological water rights among counties and corps farms can't guarantee the subject's rights and responsibilities and object's allocation of oases ecological water rights, which causes the ecological environment to become worsened in Tarim River basin. Therefore, this paper gives the definition of the allocation of oases ecological water rights among counties and corps farms, and then determines the method and model to calculate its allocation. Based on this, it calculates allocation of oases ecological water right among counties and Corps farms in Tarim River basin. The results are as follows: after the allocation of oases ecological water rights among counties and corps farms in Tarim River basin is included in its administrative primary allocation of water rights and water administrative licensing is issued, the subject's rights and responsibilities and object's allocation of the oases ecological water rights can be implemented systematically; and what's more, in three headstreams of Tarim River and upper, middle and lower reaches of the main stream, the allocation of oases ecological water rights among counties and corps farms is mainly in relatively economically developed cities and the big agricultural counties and corps farms with large cultivated land areas and lots of populations; its yearly allocation is mainly from March to May and from June to September, among which the allocation of suitable oases ecological water rights and the allocation of oases ecological water rights of maintenance and restoration are much higher. All this will provide references for the allocation of oases ecological water rights among counties and corps farms in Tarim river basin.