Reducing the liquefaction potential of a soil caused by earthquake has been increasingly investigated. One of the liquefaction mitigation methods is to generate excess pore water pressures in the liquefiable soils. The goal of this study is to investigate the liquefaction characteristics of porous material (PM) and its application in improving the liquefaction resistance of saturated sandy soil. Samples were prepared under loose state and tested under undrained stress-controlled conditions. A series of cyclic triaxial tests were conducted on various conditions such as loading frequency (f) and height-to-diameter ratio (H/D). For the investigation of liquefaction mitigation of fine sand, a comparative study was conducted on the same gradation of PM and coarse sand specimens. The experimental results showed that the effect of the f on the cyclic resistance ratio (CRR) of PM was negligibly minor under f between 0.05 and 1 Hz, regardless of the sample size. Under the same testing conditions, an ignorable effect of specimen sizes on CRR of PM was found under various H/D ratios between 1.6 and 2.8. For the application of PM in geotechnical engineering, while PM specimens have the greatest liquefaction resistance value compared to fine sand and coarse sand, fine sand mixed with 30 % PM, by weight has more resistance than the same gradation of fine and coarse sand mixture by approximately 14 %.