Main catalyst of olefin polymerization catalyst, preparation method thereof, and olefin polymerization catalyst

A main catalyst of an olefin polymerization catalyst comprises the following components: a magnesium compound carrier, transition metal halides, C2-C15 alcohols, and asteroid organic aza-ether compounds. The preparation method of the main catalyst comprises the following steps: (1) dispersing a magnesium compound carrier into an inert organic solvent, adding C2-C15 alcohols into the solvent, and stirring to dissolve the alcohols; (2) cooling the solution obtained in the step (1), and adding asteroid organic aza-ether compounds to carry out reactions; and (3) contacting the system obtained in the step (2) with transition metal halides at a temperature of -25 to 30 DEG C, after reactions, washing the reaction products by toluene or n-hexane, filtering to remove unreacted substances, and carrying out vacuum drying to obtain the main catalyst. An olefin polymerization catalyst comprises the abovementioned main catalyst and an auxiliary catalyst, which is one of trimethyl aluminum, triisobutyl aluminum, tri-n-hexy