A series of artificial silt with different sand ratios (10%,20%, 40%) is prepared, with the improvement tests, the improvement effect of different modifiers(lime and sodium silicate, lime and fly ash) with different proportion on silt has been investigated. the results show that with the increase of sand rate, either soil or modified soil, the maximum dry density increases; contrary to the lime and fly ash modified soil, the maximum dry density of lime and sodium silicate modified soil is significantly reduced; the optimum moisture content of lime and sodium silicate modified soil and soil is slightly different, however, for lime, fly ash modified soil and soil, the optimum moisture content is basically the same; with the same sand ratio, the maximum degree of compaction and the optimum moisture content of the lime and sodium silicate modified soil with different ratios have not changed greatly, the compaction ratio of 10% lime and 20% fly ash is higher than the others; at a constant degree (95%) of compaction, the unconfined compressive strength of modified soil is significantly higher than silt, and plays a "stable" effect, the modified additive quantity is the key factor of the unconfined compressive strength.