The invention discloses a preparation method of tetragonal-phase-based sulfur-rich sulfated zirconia, which comprises the following steps: dissolving zirconium n-butoxide and ammonium persulfate in benzyl alcohol to obtain a solid phase, carrying out vapor-phase reaction by using distilled water as a liquid phase, and carrying out high-temperature roasting on the obtained solid product to obtain the sulfated zirconia. The sulfated zirconia has the characteristics of rich sulfur, tetragonal phase and uniform acidic potential distribution, and has excellent catalytic activity in the field of acid catalysis application.