The invention relates to a magnesium-calcium-zirconium brick manufactured by means of in-situ reaction and used for secondary refining and a production method. During manufacturing, 0-20% of 3 mm-5 mm magnesia particles, 30-55% of 1 mm-3 mm magnesia particles, 4-15% of 0.088 mm-1 mm fine magnesia particles, 2-10% of 0.088 mm-0.5 mm fine desilicated zirconia particles, 5-30% of magnesia powder with the diameter being less than 0.088 mm, 0-15% of calcium zirconate powder with the diameter being less than 0.088 mm, 2-9% of zirconia micro powder with the diameter being less than 0.020 mm, 2-8% of calcium carbonate micro powder with the diameter being less than 0.020 mm, 4-8% of additional waste pulp liquid and 0.2-0.05% of additional third-generation water reducing agents are used; during production, the adopted process includes the steps that firstly, the zirconia micro powder and the calcium carbonate micro powder are premixed; secondly, the 3 mm-5 mm magnesia particles, the 1 mm-3 mm magnesia particles and the 0.088 mm-1 mm fine magnesia particles are added to a mixing mill, and he waste pulp liquid and the third-generation water reducing agents are added to the mixing mill to be mixed; thirdly, magnesia powder with the diameter being less than 0.088 mm, calcium zirconate with the diameter being less than 0.088 mm and premixed zirconia-calcium carbonate micro powder with the diameter being less than 0.020 mm are add and mixed until the mixture is even; finally, forming, drying, 1580-1700 DEG C sintering and checking are conducted on the mixture to obtain a refractory material with periclase-calcium zirconate-baddeleyite as a main crystal phase. The magnesium-calcium-zirconium brick has the advantages of being convenient to manufacture, low in cost, simple to use and excellent in performance, has excellent anti-erosion performance and thermal shock resistance, excellent high-temperature physical and chemical stability, and is competent for the work of secondary refining to make clean steel.