In order to determine the compressibility characteristics of bio-enzyme expansive soil, by a series of one-dimensional consolidation tests, the effect of consolidation pressure on compressibility attributions of bio-enzyme-treated, lime-treated and cement-treated expansive soil is scrtutinized, and voids ratio, compression coefficient and unit settlement are gained. The influence of compression pressure on bio-enzyme -treated expansive soil, lime-treated expansive soil, and cement-treated expansive soil is discussed. Bio-enzyme -treated, lime-treated and cement-treated expansive soil possesses different compressibility, which is embodied by e-p curve and coefficient compressibility The compressibility of expansive soil is improved by adding bio-enzyme, lime and cement. When the mass ratio between enzyme and water is 1:300, compressibility is minimum. Linear equations can describe the relation between unit settlement and unit loads:s_i=bp^_ia.