The　effective　velocity　of　stress　wave　in　rock　masses　with　double-scale　discontinuities　subjected　to　in-situ　stresses　was　investigated　in　the　present　study.　An　improved　model　that　comprehensively　considers　the　deformation　of　macrojoint　and　wave　velocity　of　microdefected　rock　mass　under　in-situ　stress　was　proposed　to　study　the　effective　velocity　of　stress　wave.　The　effect　of　in-situ　stress　on　effective　velocity　was　systematically　analyzed　using　the　presented　model.　The　effect　of　the　propagation　distance,　incident　wave　amplitude　and　incident　wave　frequency　on　effective　velocity　under　in-situ　stresses　were　further　discussed　and　compared　with　the　results　of　traditional　study　that　disregards　the　influence　of　in-situ　stress.　The　findings　demonstrate　that　the　small　in-situ　stresses　have　a　substantial　effect　on　the　effective　velocity.　The　effective　velocity　shows　a　trend　of　rapid　increase　followed　by　slow　increase　as　increases　of　in-situ　stress.　Additionally,　the　effective　velocity　increases　with　propagation　distance　and　amplitude.　In　the　low　and　high-frequency　regions,　the　effective　velocity　remains　approximately　at　minimum　and　maximum　values.　A　significant　increase　in　the　effective　velocity　is　observed　as　the　frequency　increases　in　the　mid-frequency　region.　However,　it　is　noted　that　the　effective　velocity　does　not　change　significantly　with　increasing　amplitude　for　sufficiently　large　in-situ　stresses,　and　the　influence　of　amplitude　on　the　effective　velocity　can　be　disregarded.　Furthermore,　it　is　found　that　the　effective　velocity　resulting　from　the　present　study　is　consistently　larger　than　that　resulting　from　the　traditional　study　due　to　the　effect　of　the　in-situ　stress.　The　findings　of　this　investigation　offer　useful　theoretical　guidance　for　research　into　the　effective　velocity　in　deep　rock　mass.　©　2024　Elsevier　Ltd