This　study　aims　to　prepare　cement　mortar　with　different　proportions　of　artificial　geopolymer　sand　(AGS)　and　investigate　its　dynamic　mechanical　properties.　Firstly,　AGS　was　used　to　replace　natural　sand　(NS)　to　obtain　cement　mortar　with　different　proportions　of　AGS　(0.0%,　20.0%,　40.0%,　60.0%,　80.0%　and　100.0%).　Secondly,　the　dynamic　impact　test　was　conducted　on　cement　mortar.　The　dynamic　stress-strain　relationship　was　obtained.　Finally,　the　effects　of　AGS　replacement　rate　and　strain　rate　on　dynamic　mechanical　properties　(dynamic　strength,　elastic　modulus,　energy　absorption　and　dynamic　increase　factor　DIF)　of　cement　mortar　were　discussed.　The　results　show　that　the　dynamic　strength,　elastic　modulus　and　energy　absorption　of　cement　mortar　increase　firstly　and　then　decrease　as　replacement　rate　increases　at　a　fixed　impact　pressure,　while　DIF　decreases　firstly　and　then　increases　with　replacement　rate　increasing.　The　dynamic　strength,　elastic　modulus　and　energy　absorption　reach　the　maximum,　the　DIF　reaches　the　minimum　at　the　replacement　rate　of　20.0%.　In　addition,　the　dynamic　strength,　DIF　and　energy　absorption　of　cement　mortar　significantly　increase　as　strain　rate　increases,　showing　an　obvious　rate　dependence.