The　preparation　of　ultra-high-performance　concrete　(UHPC)　with　both　high-early-strength　and　good　workability　contributes　to　further　promotion　of　its　development　and　application.　This　study　investigated　the　effects　of　different　accelerators　(SM,　alkaline　powder　accelerator;　SF,　alkaline　powder　accelerator　containing　fluorine;　and　AF,　alkali-free　liquid　accelerator　containing　fluorine)　on　the　workability　and　strength　properties　of　UHPC.　The　microstructure　of　UHPC　was　also　characterized　by　using　XRD　and　SEM.　Several　dosage　levels　of　accelerators　(2%,　4%,　6%,　and　8%　by　mass)　were　selected.　The　results　indicate　that　the　setting　time　and　fluidity　of　UHPC　are　grad-ually　decreased　with　an　increase　in　accelerators　dosage.　Compared　with　fluorine-containing　SF/AF,　fluorine-free　SM　evidently　facilitates　UHPC　early　strength　gain　speed.　However,　the　fluorine-con-taining　accelerators　have　a　higher　28　d　strength　ratio,　especially　AF.　The　maximum　compressive　and　flexural　strength　ratios　are　obtained　at　a　dosage　of　6%,　which　are　95.5%　and　98.3%,　respectively.　XRD　and　SEM　tests　further　reveal　the　effect　of　different　accelerators　on　the　macroscopic　properties　of　UHPC　from　the　micro　level.　©　2021　by　the　authors.　Licensee　MDPI,　Basel,　Switzerland.