Abstract: The carbon fiber reinforced polymer (CFRP) hat-stiffened plate which is fabricated in wide-bodied airplane is concluded in line with manufacturing crafts of automatic fiber placement (AFP) and autoclave forming that is very complex, so it is necessary to make theoretical research and modeling. Viscoelastic mechanics and percolation model were used to simulate the AFP process, while the composite material heat conduction, curing crosslinking chemical reaction, curing dynamics and porous media percolation model were employed in the simulation of the autoclave process, every multidisciplinary model sharing coupling relationship. On this base, numerical simulation of curing process of manufacturing simple carbon fiber reinforced epoxy resin multilayer under the AS4/3501-6 resin system was carried out. The consequences of simulation were verified when compared with the experimental results. Applying this approach of simulation in CFRP hat-stiffened plate, the results manifest that: (1) The operating head of the AFP equipment can generate a sag whose extend is related to the mandrel’s supporting property, after adding the supporting structure, the simulated sag value and the affecting area value decreases to 38% and 30% compared with the original mandrel; (2) The internal temperature of the hat-stiffened plate is different from the setting process temperature, and the maximum temperature appears in the early heating stage after the end of the insulation process, the predicted value is 106% of the process temperature, and the temperature difference between the inner and outer layers at the joint is obvious; (3) The internal viscosity of the hat-stiffened panels decreases first and then increases sharply, and the change rate of the inner layer viscosity is greater than that of the outer layer; (4) The predicted average skin thickness of the hat-stiffened plate reduces from 4.5 mm before forming to 4 mm, the measured thickness is 3.88 mm, the simulation error is 3.1%.