The invention relates to synthesis of a series of novel asymmetric hybridized phosphine-aminophosphine ligands for alpha-olefin catalytic system preparation through selective oligomerization of ethylene, belongs to the field of organic synthesis, relates to synthesis of a phosphine-aminophosphine structure skeleton-containing ligand in an alpha-olefin catalytic system prepared through selective oligomerization of ethylene, and provides a ternary catalyst system using chromium as a central metal precursor and using a phosphine-aminophosphine compound as a ligand, activator or co-catalyst, and applications of the ternary catalyst system in catalytic synthesis of 1-hexene through high selectivity ethylene trimerization and in catalytic synthesis of 1-octene through high selectivity ethylene tetramerization. Compared to the traditional PNP chromium-based catalyst system, the ternary catalyst system of the present invention has the following advantages that the co-selectivity and the activity of 1-hexene and 1-octene are improved, the waxy product is reduced, the reaction conditions are mild, and the high activity is maintained.