One new cadmium complex [Cd(phen)3]·(ClO4)2·(p-MBA)2·(H2O)2 has been hydro-thermally synthesized by reacting p-methylbenzoic acid (p-MBA),1,10-phenanthroline (phen) and cadmium perchlorate. It crystallizes in the triclinic system,space group P1,with a=1.2809(3),b= 1.3431(3),c=1.3734(3) nm,α=84.259(4),β=71.603(3),γ=74.424(3)o,V=2.1594(8) nm3,Dc= 1.532 g/cm3,Z=2,F(000)=1008,μ=0.697 mm-1,R=0.0646 and wR=0.1648. The crystal structure shows that the cadmium ion is coordinated with six nitrogen atoms from three 1,10-phenanthroline molecules,forming a distorted octahedral coordination geometry. The result of electrochemical property analysis shows that the electron transfer in the electrode reaction is irreversible.