The invention discloses a sample for detecting the corrosion behavior of porous metal and a preparation method thereof. The sample includes a conductive body made of a dense metal material, and a conductive wire is electrically connected to the conductive body. One end of the conductive body is welded with a reactor made of the porous metal material, the conductive body is packaged in a packagingbody made of a corrosion-resistant insulating material, the packaging body is cut off at the junction of the conductive body and the reactor, the packaging body reaches out of the conductive wire, andsignals can be transmitted. The invention also discloses a detection method for the porous metal corrosion behavior. The method comprises steps: the sample is soaked, the sample at different soakingtime points is detected, a voltaic potential distribution condition changing along with the time for the non-porous area on the surface of the reactor and the inner part of the pore structure of the reactor is obtained, and based on the voltaic potential distribution condition, the corrosion characteristic differences between the corrosion behaviors inside and outside the pores of the porous metalare compared and analyzed. The technical problem of being limited to detection on the overall corrosion behavior of the porous metal is solved.