The invention discloses a high-entropy alloy binder phase-based nitrogen-containing hard alloy, wherein the binder phase of the nitrogen-containing hard alloy is high-entropy alloy, and the hard phase of the nitrogen-containing hard alloy is uniformly distributed WC (Wolfram Carbide) and carbon nitride solid solution; the high-entropy alloy binder phase is at least four of iron, cobalt, nickel, chromium, aluminum, vanadium, titanium, copper, zirconium, molybdenum and manganese; the molar ratio of content of each element is 5-35 percent; the carbon nitride solid solution is at least one of Ti(Cx, N1-x) and (Ti, M1, ......)(Cx, N1-x); and M1 component in the (Ti, M1, ......)(Cx, N1-x) is at least one of W, Mo, Ta, Nb, V, Cr, Zr, Hf, Y and lanthanides. According to a preparation method of the high-entropy alloy binder phase-based nitrogen-containing hard alloy, the alloy comprises the raw material components in percentage by weight: 3-25 percent of high-entropy alloy binder phase, 45-96.9 percent of WC powder and 0.1-30 percent of carbon nitride solid solution powder, wherein the nitrogen element in the nitrogen-containing hard alloy is introduced through the carbon nitride solid solution. The preparation method of the multi-element composite carbon nitride solid solution-based nitrogen-containing hard alloy comprises the following steps of: (1) mixing through ball milling; (2) shaping; and (3) performing low-pressure sintering.