Numerical simulation of turbulent combustion and flame spread in a large complex fire has been carried out using a self-developed CFD code SMAFS to investigate the well-known Göteborg fireaccident [1]. This comprehensive computation includes modeling of turbulence, turbulent combustion, sooting, radiation, heat conduction and pyrolysis of solid fuel. In order to reduce the wall clock time toan acceptable limit, the computation was parallelized based on domain and angle decompositions and performed using 8 processors on a SGI Origin 2000 super computer. The results, including the transient development of the smoke profile, heat flux distribution and flame spread over combustible material,etc., are presented and analyzed. It is found the simulation is in a good agreement with the real fireaccident observation and helps explain the real fire phenomena.