<p>Three kinds of lanthanide-based passivation materials, i.e., lanthanum carbonate oxide (LOC), lanthanum hydroxide (LH), and lanthanum oxide (LO), were synthesized to compare the effects of their remediation on sediment endogenous P loads (EPL) under suspended particulate matter (SPM) deposition conditions, and the impact of treatment mode on the mobilization of EPL by LO, LH, and LOC was explored. LOC outperformed LO and LH in phosphate sorptive removal from aqueous solutions with potassium, sodium, sulfate, bicarbonate, chloride, and calcium ions present; however, with magnesium ions, LOC's performance was inferior to LH but still superior to LO. The primary P sorption mechanisms on LO, LH, and LOC involved ligand exchange between hydroxyl/carbonate groups and phosphate and formation of inner-sphere La–O-P complexes. And also, the generation of LaPO₄ played a crucial role in phosphate removal for LH. Under conditions with little SPM deposition, applications of LO, LH, and LOC all actively prevented EPL migration to the overlying water. Under conditions with substantial SPM deposition, SPM burial significantly reduced the inhibition of EPL liberation from sediment by one-time LO/LH/LOC capping, but induced only minor changes in the inhibitory effect of multiple LO/LH/LOC capping. As a restoration material, LH was most effective in immobilizing sediment EPL. The release risk of La is ranked as LOC &lt; LO &lt; LH. High-throughput sequencing revealed that all three materials' capping reshaped the structure of the bacterial communities, and different functional microorganisms affected the microbially-driven P cycle within the sediment. Based on this research, from ecological safety, effectiveness, and application, multiple LH capping is a hopeful way for managing EPL in eutrophic lakes.</p>