In order to improve the piezoresistance characteristics, the mortar was modified by adding CF powder and silicon powder. The piezoresistance test of specimens was carried out. The strain-resistivity curves were analyzed. The results show that the resistivity of the specimen decreases with the increase of compressive strain. The stress-resistivity curve can be divided into contact, bearing and failure stages. When the CF content is 2%, the sensitivity is the highest and the linear range is the largest. When CF content is 2%, the linear correlation coefficients of single-doped and multiple-doped specimens are 99.92% and 99.45%, respectively. When the CF content is 4%, the linear correlation coefficients of single-doped and multiple-doped specimens are 98.39% and 98.33%, respectively. When the CF content is 6%, the CF powder will agglomerate, and the stress-resistivity of the specimen conforms to an exponential relationship. In the single-dope and multiple-dope specimens, 4% is close to the percolation threshold of the CF powder content. The strength of the multiple-doped specimen is higher than that of the single doped specimen. The compressive strength of Si4/CF4 reaches 52.4 MPa. It is concluded that the Si4/CF4 specimen has higher strength, piezoresistive linearity and interval, but its sensitivity and linear interval are not as good as Si2/CF4.