In this paper, porous CoCrNi mesentropic alloys with porosity of 63%~78% and pore size of 1.3~2.2mm were successfully prepared by powder sintering and dissolution method. The pore morphology and phase composition of the samples were analyzed by SEM and XRD, and the axial quasi-static compression experiments were conducted on the samples. The results show that the elastic modulus and yield platform stress of porous CoCrNi alloy decrease with the increase of porosity and pore size. Compared with porosity, the effect of pore size on mechanical properties is low. The energy absorption values per unit volume of porous CoCrNi mesentropy alloys with different porosity range from 34.8 to 14.3MJ/m₃ ^{under d}ense strain, about 3.8 times that of aluminum foam, and the ideal energy absorption efficiency (I) of the five porosity ratios is close to 0.8, indicating that the porous CoCrNi mesentropy alloy has the potential to become an ideal energy absorption material.