The present disclosure discloses a preparation method of pressed Scandia-doped dispenser cathode using microwave sintering. Embodiments of the present disclosure include dissolving some nitrates and ammonium metatungstate with deionized water to prepare a homogeneous solution. Precursor powder with uniform size is obtained by spray drying, the precursor powder is decomposed, and two-step reduction may be proceeded to form doped tungsten powder with uniform element distribution. The cathode is prepared by one-time microwave sintering. One-time forming of cathode sintering is realized, and sintering shrinkage and sintering time are reduced significantly. The method has excellent repeatability, and the cathode has a homogeneous structure and excellent emission performance at 950° C.