The kinetics of propylene polymerization initiated by ansa-metallocene diamide compound rac-Me2Si(CMB)(2)Zr(NMe2)(2) (rac-1, CMB = 1-C5H2-2-Me-4-Bu-t)/ methylaluminoxane (MAO) catalyst were investigated. The formation of cationic active species has been studied by the sequential NMR-scale reactions of rac-1 with MAO. The rac-1 is first transformed to rac-Me2Si(CMB)(2)ZrMe2 (rac-2) through the alkylation mainly by free AlMe3 contained in MAO. The methylzirconium cations are then formed by the reaction of rac-2 and MAO. Small amount of MAO ([Al]/[Zr] = 40) is enough to completely activate rac-1 to afford methylzirconium cations that can polymerize propylene. In the lab-scale polymerizations carried out at 30 degrees C in toluene, the rate of polymerization (R-p) shows maximum at [Al]/[Zr] = 6,250. The R-p increases as the polymerization temperature (T-p) increases in the range of T-p between 10 and 70 degrees C and as the catalyst concentration increases in the range between 21.9 and 109.6 mu M. The activation energies evaluated by simple kinetic scheme are 4.7 kcal/mol during the acceleration period of polymerization and 12.2 kcal/mol for an overall reaction. The introduction of additional free AlMe3 before activating rac-1 with MAO during polymerization deeply influences the polymerization behavior. The iPPs obtained at various conditions are characterized by high melting paint (approximately 155 degrees C), high stereoregularity (almost 100% [mmmm] pentad), low molecular weight (MW), and narrow molecular weight distribution (below 2.0). The fractionation results by various solvents show that iPPs produced at T-p below 30 degrees C are compositionally homogeneous, but those obtained at T-p above 40 degrees C are separated into many fractions.