Supercritical　CO2　Brayton　cycle　is　a　good　choice　of　thermal-to-electric　energy　conversion　system,　which　owns　a　high　cycle　efficiency　and　a　compact　cycle　configuration.　It　can　be　used　to　many　power-generation　applications,　such　as　nuclear　power,　concentrated　solar　thermal,　fossil　fuel　boilers,　shipboard　propulsion　system.　Transient　cycle　analysis　for　S-CO2　Brayton　cycle　is　quite　important　in　the　area　of　transient　analysis,　control　strategy　study　and　accident　analysis.　In　this　paper,　a　transient　analysis　code　SCTRAN/CO2　is　developed　for　S-CO2　Brayton　Loop　based　on　a　homogenous　model.　Heat　conduction　model,　point　neutron　power　model(which　is　developed　for　nuclear　power　application),　turbomachinery　model　for　gas　turbine,　compressor　and　shaft　model,　PCHE　recuperator　model　are　all　included　in　this　transient　analysis　code.　The　verifications　and　validations　were　performed　for　models　like　heat　transfer　model,　friction　model,　compressor　model.　The　verification　of　integrated　system　transient　was　also　conducted　through　making　comparison　with　experiment　data　of　SCO2EP　of　KAIST　and　IST　of　Knolls　Atomic　Power　Laboratory.　The　comparison　results　show　that　SCTRAN/CO2　owns　the　ability　to　simulate　transient　process　for　S-CO2　Brayton　cycle.　SCTRAN/CO2　will　become　an　important　tool　for　S-CO2　based　Bryton　cycle　development.　©　2016　Association　for　Computing　Machinery　Inc.　All　Rights　Reserved.