To realize the efficient utilization of montebrasite, we conducted a systematic study of sulfuric acid roasting and water leaching processes. In this study, we propose a roasting process at a lower temperature than that proposed in previous studies, which can achieve the selective extraction of lithium from montebrasite and effective enrichment of aluminum and phosphorus. The thermodynamic simulation results of the reaction between montebrasite and sulfuric acid showed that the method was feasible in theory. Under the optimal conditions determined by theoretical analysis and experimental results, Li extraction reached 97.5 %, whereas Al and P extraction only reached 1.9 % and 0.1 %, respectively. The results of XRD characterization and analysis of roasting slag and leaching residue demonstrated that montebrasite was decomposed into Li2SO4, Al2(SO4)3, and H3PO4 by sulfuric acid. The temperature increase facilitated the conversion of these intermediates into Li2SO4 and AlPO4, confirming the absence of SO3 generation within the studied temperature range. Selective extraction of Li achieved water leaching through water leaching, resulting in a leaching residue with over 95 % AlPO4 content. The leaching liquor underwent purification and precipitation, resulting in the attainment of Li2CO3 with a purity level of 99.8 %. This process enables selective extraction of Li from montebrasite while efficiently enriching Al and P components. It represents an efficient and environmentally friendly approach for lithium extraction.