Abstract: The precipitation behavior of Ti(C,N) particles in CSP low carbon steel with Ti addition was studied by experimental observation and thermodynamic calculation. Large amount of fine Ti(C,N) particles with 15-30 nm in size were observed, which were precipitated and grew up during the soaking and in the first two hot rolling process. There were only a few TiN particles of more than 50 nm in size precipitated in the slabs before soaking, and no TiN inclusions larger than 1 μm were observed. The results show that the precipitation behavior in the steel produced by the CSP technology is different from that in the conventional one. The effects of small amount of Ti addition on the properties of steels are also different.