In order to find out the suitable asphalt types and corresponding voidage of the Irrigated semi-flexible pavement(ISFP), SBS modified asphalt and 70# road petroleum asphalt were used to form the matrix asphalt mixture with voidage of 10%, 15%, 20%, 25%, 30%, 35%. The Marshall specimens ISFP-13 were formed by pouring the cement-based grouting material into matrix asphalt mixture. Marshall test, rutting test, low temperature beam bending test and Freeze- thaw splitting test were used to evaluate its high temperature performance, low temperature performance and water damage resistance. The test results show that with the increase of voidage, the anti-deformation ability of SBS modified asphalt and 70# road asphalt matrix asphalt mixture becomes worse, but the performance of perfusibility becomes better. The high temperature performance and water stability performance of ISFP-13 are enhanced, but the performance of low temperature anti-fission is worse. Comprehensive consideration of the pavement performance of the base asphalt mixture and ISFP, it is suggested that the suitable voidage of 70# road asphalt in ISFP is 15%-20%, and that of SBS modified asphalt in ISFP is 15%-25%.