A typical foreland basin developed in the northern part of Tarim after Hercynian.The basin was firstly confined to the piedmont of South Tianshan during TriassicJurassic

then extended southward and covered a large area since Cretuceous. The purposeof this paper is attempting to discuss the subsidence mechanism of the basin through numerical modellins. Assuming the continental lithosphere of the area to be a uniform elasticplate

tubing Tianshan orogenic zone as tectonic loads

strata distribution modelling wasmade in five stages. The main parameters necessary for the modelling included obeervedstructural sections

fie-cural rigidity of the lithosphere and the amounts of tectonic loads.The results of the modetling are theoretic structural sections and topography of specifiedload feature. Finite element method was used to solve the fie-cure equation during themodelling process. The theoretical subsidence Plofiles show considerable fit with theobserved tectonic sections except some differences in Shaya uplitf. This indicates that thefie-cural respond of the lithosphere to Tianshan mountain loads may be used to explain themain subsidence mechanism of the basin. The parameters acquired through modelling areanalogous to some typical foreland basin during Meso-Cenozoic.