The paper concerns the causes of enhanced rainfall from Typhoon 9012(YANCY)in terms of intense observations collected in the implementation of the 1990 SPECTRUM project. Results show that the regional intense precipitation made up 64% of the total with the rainfall duration changing versus the meridional oscillation of the storm’s position;meso-α-scale torrential rainfall region was associated with northeasterly jet on the west side and an inverted trough of the tempest;the meso-β-scale heavy rain sector bore close relation to a surface vigourous easterly area,easterly perturbation,a meso convergence region,a meso cyclone,a meso frontal zone and a meso frontogenesis region.