The invention discloses a novel inhibitor for aluminosilicate minerals and a use method of the novel inhibitor. The novel inhibitor is organic composite phosphate mainly composed of amino trimethylene potassium phosphate of the small molecular weight or amino trimethylene sodium phosphate of the small molecular weight. The use method of the novel inhibitor includes the steps that when positive flotation is conducted on bauxite, the granualarity property of a bauxite grinding product with the alumina-silica ratio ranging from 3 to 5 is -0.074 mm, and the size fraction accounts for 80% to 90%; and the pH value of a flotation system is controlled from 9 to 11, sodium oleate serves as a collecting agent, and the use amount ranges from 500 g/t to 1200 g/t. The use amount of the inhibitor ranges from 60 g/t to 70 g/t. The novel inhibitor is applied to the bauxite positive-flotation desilicication process, the selective inhibition effect on minerals containing silicon can be enhanced, meanwhile the capacity of eliminating unavoidable ions such as Ca2+ and Mg2+ can be enhanced, and the effect of positive flotation of the bauxite is improved.