Abstract: The quality control of Q195L peritectic steel is difficult. In order to control  steel leakage and billet cracking during continuous casting, the high manganese sulfur ratio control in molten steel in the original process leads to high alloy costs. In addition, there are also problems such as low casting speed and low production efficiency. To solve the above problems, research was conducted from aspects such as composition of molten steel, smelting endpoint, deoxidation alloying, continuous casting process. Through practical optimization, the breakout rate of Q195L peritectic steel billet reduced from 4.2% to zero， and the continuous casting speed increased from 2.4 m/min to 3.0 m/min. The quality of billet was stable and met the requirements of steel rolling. By optimizing the composition of molten steel to reduce the strength of steel, the alloy cost reduced by 18 yuan/t.

Key words: billet, Q195L steel, casting speed, practice