The　feasibility　of　the　application　of　terahertz　electromagnetic　waves　in　the　diagnosis　of　prostate　cancer　was　examined.　Four　samples　of　incomplete　cancerous　prostatic　paraffin-embedded　tissues　were　examined　using　terahertz　spectral　imaging　(TPI)　system　and　the　results　obtained　by　comparing　the　absorption　coefficient　and　refractive　index　of　prostate　tumor,　normal　prostate　tissue　and　smooth　muscle　from　one　of　the　paraffin　tissue　masses　examined　were　reported.　Three　hundred　and　sixty　cases　of　absorption　coefficients　from　one　of　the　paraffin　tissues　examined　were　used　as　raw　data　to　classify　these　three　tissues　using　the　Principal　Component　Analysis　(PCA)　and　Least　Squares　Support　Vector　Machine　(LS-SVM).　An　excellent　classification　with　an　accuracy　of　92.22%　in　the　prediction　set　was　achieved.　Using　the　distribution　information　of　THz　reflection　signal　intensity　from　sample　surface　and　absorption　coefficient　of　the　sample,　an　attempt　was　made　to　use　the　TPI　system　to　identify　the　boundaries　of　the　different　tissues　involved　(prostate　tumors,　normal　and　smooth　muscles).　The　location　of　three　identified　regions　in　the　terahertz　images　(frequency　domain　slice　absorption　coefficient　imaging,　1.2　THz)　were　compared　with　those　obtained　from　the　histopathologic　examination.　The　tissue　tumor　region　had　a　distinctively　visible　color　and　could　well　be　distinguished　from　other　tissue　regions　in　terahertz　images.　Results　indicate　that　a　THz　spectroscopy　imaging　system　can　be　efficiently　used　in　conjunction　with　the　proposed　advanced　computer-based　mathematical　analysis　method　to　identify　tumor　regions　in　the　paraffin　tissue　mass　of　prostate　cancer.　©　2020　Current　Optics　and　Photonics.