The invention relates to a preparation of light-color C5/C10 copolymer resin. The preparation method comprises the following steps: mixing a distillate A, a C5 diolefin-enriched distillate B and a C5 monoolefin distillate C according to a mass ratio of 1 to (1 to 4) to (1 to 4), thus obtaining a polymerization raw material D; adding the polymerization raw material D in a solvent, simultaneously adding an anhydrous aluminum chloride catalyst, reacting under 25 to 90 DEG C for 2.5 to 5 hours, and then carrying out after-treatment, thus obtaining the light-color C5/C10 copolymer resin. The light-color C5/C10 copolymer resin prepared by the invention is good in compatibility, light in color and adjustable in softening points; the preparation method is simple and convenient in technology, various types of C5 and C10 raw materials can be adopted, the operatability is strong, and a wide promotion and application prospect is obtained.