High　dispersion　of　rock　mass　strength　causes　significant　difficulties　in　strength　prediction.　This　study　aims　to　investigate　experimentally　the　strength　prediction　model　for　brittle　damaged　rock　with　multiscale　initial　damage　based　on　P-wave　velocity　using　regression　analysis.　Intact　dolomitic　limestone　was　collected　from　a　deep　metal　mine　in　Southern　China.　Rock　specimens　with　different　initial　damage　degrees　were　prepared　through　the　application　of　uniaxial　compressive　stress.　Both　intact　rock　and　damaged　rock　specimens　were　tested　for　P-wave　velocity　and　uniaxial　compressive　strength　(UCS).　The　test　results　indicate　that　the　method　of　prefabricating　initial　damage　to　the　rock　mass　through　uniaxial　compressive　stress　is　feasible.　The　UCS　values　of　the　damaged　rock　specimens　were　correlated　with　the　square　of　the　P-wave　velocity　(linearly　positive)　and　the　initial　damage　(linearly　negative).　The　parameters　of　the　new　strength　prediction　model　have　a　physical　significance,　and　its　results　are　within　the　upper　and　lower　limits　of　the　95%　confidence　interval　of　the　UCS.　The　strength　prediction　model　considering　multiscale　initial　damage　based　on　P-wave　velocity　could　reasonably　predict　the　strengths　of　brittle　rock　masses.　©　2022　by　the　authors.