The invention discloses a co-catalyzing preparation method of alpha, betal-diamino acid derivative of alpha-quaternary carbon. The alpha, betal-diamino acid derivative of alpha-quaternary carbon is synthesized by a reaction of three components: aryl acetic acid ester diazonium, arylamine, and sulfamide imine under co-catalysis of rhodium acetate squaric acid amide or metal magnesium salt. The alpha, betal-diamino acid derivative of alpha-quaternary carbon comprises a threo form alpha, betal-diamino acid derivative of alpha-quaternary carbon and an erythro form alpha, betal-diamino acid derivative of alpha-quaternary carbon shown as formula (II). The raw material provided by the invention is low in cost and easily available, and two chiral carbons are constructed at the same time by a one-pot method. The method is short in preparation line, simple to operate, mild in reaction condition, easy to synthesize the catalyst, high in atomic economy, high in yield and free from environmental pollution, and the threo form or / and the erythro form alpha, betal-diamino acid derivative of alpha-quaternary carbon can be conveniently obtained at the same time. A diversified compound framework is provided, and the method has important meaning on new medicine screening and pharmaceutical preparation technology.