The　excessive　extraction　and　utilization　of　river　sand　may　lead　to　the　destruction　of　river　eco-systems.　The　use　of　manufactured　sand　as　a　substitute　for　river　sand　can　effectively　avoid　the　aforementioned　issues.　However,　there　are　significant　differences　in　the　strength　of　mortar　or　concrete　prepared　using　different　types　of　sand.　The　influence　law　for　lithological　characteristics　of　three　types　of　manufactured　sand　on　mortar　strength　was　investigated　in　depth.　The　core　causes　of　strength　variation　influenced　by　different　parent　rocks　were　explained　based　on　various　macroscopic　and　microscopic　test　methods.　The　results　of　the　flexural　and　compression　tests　showed　that　the　different　parent　rock　types　would　have　a　significant　effect　on　the　mortar　strength,　where　molybdenum　tailing　sand　had　the　largest　increase　in　28d　strength　of　17%.　In　addition,　as　decreasing　the　interfacial　transition　zone　(ITZ)　volume　fraction　and　increasing　the　elastic　and　hardness　moduli　of　ITZ,　the　mortar　strength　gradually　increased.　This　study　showed　that　using　manufactured　sand　as　a　substitute　for　river　sand　reduced　extraction　and　improved　mortar　strength　while　maintaining　workability.　Molybdenum　tailings　sand　performed　the　best,　which　was　sig-nificant　for　sustainable　construction　and　environmental　protection.