The invention discloses a preparing method for a metal-ceramic based cubic boron nitride sintered joint block. Firstly, simple substance metal powder Co, Cr, Fe, Ni and Ti is subjected to ball millingand mixing according to the proportion, and high-entropy alloy powder is formed; and then, the high-entropy alloy powder, cubic boron nitride abrasive materials, ceramic hollow balls and a wetting agent are subjected to secondary mixing, then, pre-pressing is conducted, a grinding wheel blank is manufactured, finally, pressurizing sintering is conducted in an argon atmosphere sintering furnace, and the joint block is manufactured after cooling. Since metallurgical bonding can be formed by the active element Ti contained in a high-entropy alloy, the cubic boron nitride and the ceramic hollow balls, the holding strength of the cubic boron nitride is improved. Through the ceramic hollow balls contained in the joint block, the scrap containing space of a manufactured grinding wheel can be better enlarged, and the grinding efficiency of the grinding wheel is improved.