The invention discloses a method for producing high-octane gasoline by light hydrocarbon non-hydrogenation modification, which comprises the following steps: mixing catalytic cracking dry gas and light hydrocarbon, and performing modification reaction in the presence of a non-hydrogenation modification catalyst, wherein the ethylene contained in the catalytic cracking dry gas accounts for 1 to 30percent of the mass of the total feed of a reactor, and the light hydrocarbon is a C4 mixture or a mixture of the C4 mixture and distilled gasoline. The method of the invention can make full use of the catalytic cracking dry gas and the C4 mixture rich in a refinery to produce gasoline blending components and good-quality liquefied gas with low olefin content and high octane value.