In　this　paper,　a　numerical　scheme　for　simulation　of　DC　potential　drop　(DCPD)　signal　is　updated　at　first　to　deal　with　multiple　defects　in　order　to　reconstruct　multiple　cavities　in　metallic　foam　(MF)　from　measured　DCPD　signals.　A　hybrid　inversion　strategy　combining　the　genetic　algorithm　and　the　steepest　descent　optimization　method　is　proposed　then　to　evaluate　the　size　and　position　parameters　of　the　multiple　defects.　As　example,　simulated　signals　with　artificial　noise　are　adopted　to　reconstruct　the　profile　of　double　cavity　defects.　The　numerical　results　validated　the　hybrid　inversion　strategy　and　the　updated　forward　scheme　for　sizing　the　multiple　defects　in　metallic　foam.