The present invention relates to silicon ether compounds having a general formula (I), a method for the preparation thereof and use thereof as a component of catalysts for polymerization of olefins. In particular, in propylene polymerization, catalyst systems comprising the silicon ether compounds as external electron donor component exhibit good hydrogen response, and can be used to prepare polymer having high isotacticity at high yield. ##STR00001## wherein R.sub.1-R.sub.10 groups are as defined in the description.