The 20 soil rock composite media test specimens with soil rock ratio of 9∶1,7∶3,5∶5,4∶6, and the compaction degrees of 90%,92%,95%,98%,100% were prepared in the condition of optimum water content. Through measuring the variations of resistivity during the water absorption process, the variable relationship between the resistivity and soil rock ratio, compaction degree as well as their causes were clarified, moreover,the compaction degree and saturation index were correlated during the saturation process, finally, the unsaturated model of resistivity saturation was used to fit the variation law of soil rock composite media resistivity with saturation, the generally fitting results are good. This study can provide data support for the use of resistivity to detect seepage channels formed by water absorption and saturation of soil rock dam materials.