Abstract: The super typhoon "Meranti" (1614) landed at Xiamen City and produced extremely heavy rain in the central-northern Fujian Province during 14-15 September 2016. A slow-moving long-lasting intensive convective spiral rain-band in the northern and northeastern parts of the typhoon circulation led to the extremely heavy rain after the typhoon made its landfall. A large-domain numerical modelling without nesting was carried out to simulate the extremely heavy rain produced by the landfalling typhoon "Meranti" using mesoscale numerical model WRF (V3.9). The model accurately simulated the intensity and location of the extremely heavy rain, and successfully reproduced the formation and development of the long-lasting intensive convective spiral rain-band after the typhoon made landfall. Analysis of the results indicates that several scattered mesoscale convergences were organized into a mesoscale convergence band and triggered the intensive convective spiral rain band, which maintained and developed for a long time and moved northeastward slowly after they moved into the area of weak-wind shear, positive vorticity band and moist static energy (pseudo equivalent potential temperature, specific humidity) front in the downstream of the Taiwan topography. The Taiwan topography plays a very important role in the formation of the mesoscale environment favorable for the long-time maintenance and development of the mesoscale intensive convective spiral rain-band. The topographic effect is helpful for the formation of a positive vorticity band (positive potential vorticity band) and a low moist static energy area to the south of the rain band (that is, a moist static energy front) in the downstream of the Taiwan topography, which is very important for the long-time maintenance and development of the mesoscale intensive convective spiral rain-band. The results of topographic sensitivity experiment further verify the important role of the Taiwan topography in the formation and maintenance of the long-lasting intensive convective spiral rain-band in the northeastern part of the typhoon circulation after the typhoon made landfall.