From surveying the advance - booking of our country ' s commercial housing , analyzing the mortgage in hong kong ' s law , researching the present situation and perspective of our country ' s mortgage practice , studying specially the discrimination between mortgage and charge as well as pledge , the author deduces that guarantee object of advance - booking of commercial housing is the reversionary right , and the advance - booking of commercial housing should be classified into the cessionary guarantee system in expectation of benefit to the legislation of our country ' s property right law 本文从对我国商品房预售概述和香港法上的按揭分析、从我国按揭实务现状及问题透视的研究、从按揭与抵押、质押的区别作了专门的研究,认为商品房预售按揭的担保标的物是期待权、商品房预售按揭应归于让与担保制度范畴的结论,以期对我国物权法的立法有所裨益。