We presented the conduction mechanism investigation of porous silicon/p-Si heterojunction fabricated on low resistivity crystalline silicon by electrochemical anodization. Measurements of the current – voltage I(V) and capacitance – voltage C(V) characteristics were used for the study of the electrical properties of this heterojunction. A deeper understanding of the physical mechanisms involved in the Au/porous silicon contacts and porous silicon/p-Si interface can be obtained from the voltage dependence of the fitting parameters according to electrical model circuits in DC and AC. We found in the heterojunction important conduction mechanisms: the resonant tunnelling, SCLC and the dielectric relaxation due to the pores layers at high frequencies.