Writer found that the bottom boundaries of the Zhangzhou basin and more than 10 small basins nearby were mostly in accord with the boundary lines of the granodiorite occuping these basins，the sedimentary strata of these basins were very thin，the piedmont denudation surface were quite large；the higher landform around these basins were mainly acid，intermediate—acid volcanic rocks or ultra hypahyssial intrusive rocks，there were no direct geological evidenes of normal faults on the boundaries of these basins. So, further according to the different denudation rates of different rocks，it is considered that the Zhangzhou basin was formed by erosion and not belongs to the socalled tectonofault basin. The ascertation of the genesis for this type of basins has an important significance for the seismic detection.