Artificial　muscle　is　a　bio-inspired　soft　actuator　that　generates　large　output　force　and　displacement　with　flexibility　and　compliance　and　can　interact　with　humans　and　biological　environments.　Due　to　low　load　capacity,　high　hysteresis,　and　short　life　cycle　of　existing　artificial　muscles,　a　new　kind　of　twisted　and　coiled　artificial　muscles　based　on　polymer　fibers,　such　as　nylon,　has　been　developed　and　called　twisted　and　coiled　polymer　fiber　(TCPF).　This　artificial　muscle　is　capable　of　straining　more　than　40%,　which　has　a　load　capacity　of　up　to　100　times　higher　than　that　of　a　human　muscle,　has　energy　density　of　up　to　5.3　kW/kg,　and　it　is　a　hot　topic　in　current　research.　This　study　reviews　the　development　of　state-of-the-art　TCPF,　focusing　on　fabrication　and　actuation　mechanism,　new　materials　and　structures,　improvements　on　actuation　strategy,　and　applications　in　soft　robotics.　Current　states　are　summarized　and　discussed　for　future　development　directions.　©　2021,　Science　Press.　All　right　reserved.