For a long time, Ni/ZnO reactive adsorption desulfurization adsorbent have suffered from low desulfurization performance and poor regeneration efficiency. In this paper, a series of Ni/ZnMOx composite metal oxide adsorbents are prepared by introducing the third metal M (Mn, Co, Mo) into ZnO to enhance their sulfur capacity and thermal stability. By employing DFT calculation, the feasibility of forming composite metal oxides in terms of thermodynamics is confirmed. The formation mechanism of composite metal oxides ZnMOx are finely investigated by XRD and TG-MS. Thanks to the unique structure of ZnMOx, the particle size and thermal stability of ZnO-based adsorbents are improved prominently. Experimental results demonstrate that the addition of the third metal can promote the desulfurization performance. It’s important to note that the desulfurization rate of NZCo and NZMo remains above 98% after high temperature calcination. Through characterizing the adsorbents before and after reaction, the desulfurization reaction mechanism for the Ni/ZnO adsorbent doped with metal M (Mn, Co, Mo) has been proposed. In this mechanism, Ni mainly acts as the desulfurization active centre, while ZnO and the generated composite metal oxides play the role of sulfur adsorbents. This study will provide a new idea for the rational design of conventional Ni/ZnO adsorbent to improve its desulfurization performance and thermal stability.