The process of partial hydrolysis reaction of TMA with water and the interaction of zirconocene dichloride (Cp2ZrCl2) with TMA, MAO, and the in situ partially hydrolyzed products of TMA were studied by in situ H-1- and Al-27-NMR spectroscopy. The H-1-NMR spectra of MAO samples and the in situ hydrolyzed products of TMA with water under different conditions are different. A new peak at delta = -0.58 ppm in H-1-NMR spectra is observed, and is supposed to be due to the methyl resonance of MAO with low molecular weight. Alkylation reaction is observed between Cp2ZrCl2 and TMA, MAO, and the in situ hydrolyzed products of TMA, and TMA is supposed to be the actual alkylating agent. Al-27-NMR studies show that MAO is tetra-coordinated.