Abstract: The present invention relates to a low-temperature co-fired ceramic powder and a preparation method and application thereof. The material composition of the low-temperature co-fired ceramic powder is xRO-yM2O3-zXO2, where R is at least one of Mg, Ca, Ba, Zn, Cu, and Pb, M is at least one of B, Al, Co, In, Bi, Nd, Sm, and La, X is at least one of Si, Ge, Sn, Ti, Zr, and Hf, 0?x?85 wt %, 15 wt %?y?90 wt %, 10 wt %?z?85 wt %, and x+y+z=1; and the low-temperature co-fired ceramic powder is obtained by high-temperature melting, quenching, and recrystallization treatment. The temperature of high-temperature melting is 1,200° C. to 1,600° C., and the temperature of recrystallization treatment is 500° C. to 900° C.