Abstract：During late Mesozoic-Cenozoic，FiYS inversion structure in Tuha basin underwent the following main tectonic evolution phases:tensile stretch，compressed uplifting，extensional depression and severely compressed folding. In tensile stretch phase，the basin stretched，and normal fault caused tectonic element of half graben like basin. In compressed uplifting phase，basin uplifted beacuse of compression，and normal fault became overthrust one，with weak folding. In the extensional depression phase，the basin stretched again，and overthrust fault turned into normal one，with depressive sediments in the basin. In the severely compressed folding phase，normal fault changed to overthrust one again because of terrible compression，and folding happened near fault，resulting in positive inversion structure and complicated stratum relations. The late terrible folding and inversion created favourable geological structure for hydrocarbon accumulation;but they also damaged some whole structural trap and corresponding reserve conditions，which is unfavourable to the formation of structural hydrocarbon accumulation.
