The invention relates to a process for removing calcium in primary brine by acetylene clean waste sodium hypochlorite. Crude brine without magnesium ions and phosphorus-containing liquid are subjectedto mixed reaction, and then sodium carbonate solution with the concentration of 8-15% is added and subjected to reaction to control calcium content. The phosphorus-containing liquid is prepared by the steps: mixing and compounding acetylene clean waste sodium and concentrated sodium to form sodium hypochlorite solution with the effective chlorine content of 0.08-0.12%; adjusting the pH (potentialof hydrogen) value of the sodium hypochlorite solution obtained by compounding to range from 2 to 4 by acid; performing normal-temperature stirring reaction for 20-50 minutes to obtain the phosphorus-containing liquid. According to the process, calcium is removed by waste raw materials including the waste sodium hypochlorite, calcium removing effects are good, and production cost is saved.