The performances of propylene polymerization with a TiCl4／MgCl2／9,9-bis(methoxymethyl)fluorine (BMMF)catalytic systenm in the absence of external donor were studied at various temperatures．The influences of alkylaluminiums were investigated．The results showed that i-Bu3Al and Hex3A1,which shewed weaker coordination and alkylation than Et3Al and Me3Al,resulted in higher activity and isospeeificity at lOO ℃．With Me3 Al the catalyst produced higher proportion of steroblock polypropylene than with other alkylaluminiums．The isotactic polypropylene obtained with Et3 Al contained ethylene units when the ratio of Al to Ti was 150 at 100℃．However,the isotaetie polypropylenes obtained with iBu3 Al and Hex3 Al at 100℃ did not contain isobutene and hexene units．