Abstract: With the gradual depletion of high-grade iron ore resources, the usage amount of low-grade iron ore is increasing year by year. Moreover, given the environmental protection requirements and the objective to reduce industrial cost, the usage of scrap is significantly increasing. The above occurrences have led to a large increase in the percentage of residual elemental arsenic in steel. Also, the requirement for lower arsenic content in finished steel is increasingly stricter. Presently, the iron and steel enterprises have not yet developed a mature technology for dearsenication in molten steel; moreover, the theoretical studies on the dearsenication in molten steel are relatively few, which lead to a lack of relevant theoretical data. Therefore, how to realize an effective method for dearsenication in molten steel is a technical problem in the iron and steel industry. Considering the problems of poor dearsenication in the steelmaking process and the previous experimental results of dearsenication in laboratory. The dearsenication in the process of steelmaking was investigated through an industrial trial of dearsenication in the molten steel in the ladle furnace (LF) refining furnace. The Al–Mg–Ca alloy was chosen as dearseicating agent, The industrial test about dearsenication in the molten steel show: the dearsenication in the molten steel can be realized in the LF furnace, the sulfur and calcium content in the molten steel is restrictive factor for dearsenication under industrial condition; the control level of sulfur and calcium in molten steel is put forward to ensure the effect of dearsenication. The sulfur content in molten steel must be reduced to less than 0.01% before dearsenicating in LF furnace, the calcium should be higher than 0.0055% after adding Al–Mg–Ca alloy.