Ultra-high-performance　concrete　(UHPC)　is　renowned　for　its　exceptional　strength　and　durability,　but　the　undesirable　high　material　cost　due　to　the　considerable　expense　of　reinforcing　steel　fiber　hinders　its　wide　application.　The　incorporation　of　more　sustainable　and　light　synthetic　fibers　presents　a　promising　avenue　for　lowering　the　price　and　weight　of　UHPC　while　affecting　the　rheological　and　hardened　behavior　of　UHPC.　This　paper　conducts　a　comprehensive　review　of　the　key　parameters　of　synthetic　fibers,　including　content,　aspect　ratio,　and　surface　properties,　and　their　impacts　on　the　fresh　properties,　mechanical　performance,　durability,　and　volume　stability　of　UHPC.　Particular　emphasis　is　placed　on　the　early　and　long-term　performance　of　UHPC.　Additionally,　the　sustainability　of　UHPC　with　various　types　of　synthetic　fibers　is　compared.　By　delving　into　these　aspects,　this　study　aims　to　furnish　a　constructive　reference　for　engineers　and　decisionmakers　regarding　the　utilization　of　synthetic　fibers　in　UHPC　to　achieve　optimal　early　and　longterm　performance.