Abstract: In order to solve the nozzle clogging in the compact strip production (CSP) process of high-content aluminum steel,the steel composition and inclusions before and after the calcium treatment were analyzed,and thermomechanical analysis based on Björkvall model was also carried out. The results show that theSandCaare both too high,as a result,CaS and high-content CaS inclusions are the main causes of the clogging. According to the Al-Ca-S equilibrium diagram,when the high-content aluminum steel, whoseAl_s is at 0.32% to 0.39%,is prepared,in order to prevent the formation of CaS in casting process,theSin steel should be controlled less than 0.002 0% andCain the molten steel should be controlled in the range of 0.004 0% to 0.008 5%.