Abstract: Aimed to address the expansive soil problem in highway construction in the centre of Anhui Province,typical soil specimens from the He-Liu-Ye expressway are chosen to carry out systematically experiments to study the characteristics of California Bearing Ratio(CBR) of expansive soils,and based on this the usability of expansive soils as subgrade materials is discussed.The research shows:(1)The initial water content affects the CBR value markedly,and the initial water content corresponding to the maximum CBR value is high than the optimal initial water content,and the discrepancy grows with the compaction work;(2)The CBR swell amount reduces when the initial water content increases.The CBR swell amount is higher as the initial water content is lower,and the roadbed water-stability is worse;(3)The optimal initial water content is lower when the compaction work is greater,and the range of variable water content suitable to pad is wider.So the heavy compaction standard is suggested in the site construction control;(4) In the condition of heavy compaction standard,the low-class expansive soil can meet both the compactioness request and the CBR request to pad the bottom of embankment,the middle-class expansive soil must be treated as roadbed padding materials.The results of the research could be referred to the construction of expressway in the expansive soil areas.