Ganzhou County is the main portion of Zhanye Oasis in Heihe river basin. Research on structure of population scale and spatial distribution of urban system in Ganzhou County based on fractal theory indicated :①the population scale structure is loose , and the law of the primate town is too big , but the middle towns are absent ; ②the spatial distribution of urban system is relative concentrative , and towns mainly lied in Heihe river system and traffic lines ; ③it is obvious that water resources made an restriction impact on spatial distribution of urban system; ④the traffic basis is good , but the inte- raction ability is weak. The construction of urban system in future must abide by principally t he " T" style in spatial distribution , and firstly develop the towns with good basis , continually perfect the traffic network , and what’s more , reasonably exploit water resources and protect ecological environment .