The expanded graphite (EG) prepared by electrochemical oxidation method was used as the carbon framework. The PANI/EG interlaminar composites, with tower-like porous polyaniline (PANI) coated on the surface of graphite layers orderly, were constructed via a vacuum-assisted intercalation in-situ oxidation polymerization method. The PANI/EG composites were characterized by SEM, TEM, XRD, FTIR, Raman, XPS and BET. The electrochemical detection of Cd2 were tested by SWASV, and the electrochemical properties were examined using CV and EIS. The results showed that the PANI/EG composites exhibited layered hierarchical structure. The PANI/EG12 modified electrode with EG content of 12% was employed for Cd2 electrochemical detection. The sensitivity was 7.814 μA/μM, the limit of detection was 3.24 nM and the linear range was 0.25~6 μM. The sensor has good repeatability and anti-interference.