A new method is proposed to determine the fluid catalytic cracking catalyst deactivation and kinetic parameters of a 6-lump model of catalytic cracking, using few microactivity test (MAT) experiments. instantaneous pressure drop and outlet gas flow rare are recorded during the test. The parameters of the deactivation functions. related to catalyst coke content, are obtained using these data, a simple kinetic model and a reactor model. These functions greatly depend on the catalyst nature and reaction temperature. This method allows us to adjust non-correlated deactivation function and kinetic parameters.