Aiming at widespread presence of expansive soil which canbe obtained in the project from Xiaoxita to Yaqueling first-class highway rebuilding engineering in Yichang City of Hubei Province and weathered sand which can be made full use of locally, many experiments were made. Compaction experiments and expansibility index indoor experiments of undisturbed expansive soil and expansive soil mixed with sand range from 10 % to 50 % were made. Through the test of undisturbed expansive soil mixed with different content of weathered sand, it was found that undisturbed expansive soil mixed with weathered sand can change the expansive soil water characteristics and compaction characteristics. Undisturbed expansive soil mixed with different content of weathered sand can influence the expansibility of the expansive soil index and significantly inhibit the expansibility of the expansive soil and reach the standard of roadbed filler.