This study investigated the influence of chemical remediation agents (Bc, M, HA, and Bc + HA) on the growth of the halophyte and the mechanism of restoration of soil salinization using joint halophyte and chemical remediation in arid fields. The results showed that aboveground organ biomass of increased significantly with the chemical remediation agents analyze but the effects on the root system were different. Among the root traits, dry weight of the taproot of increased significantly ( < 0.05) by 60.57% with HA; however, the lateral roots were inhibited. With the addition of biochar, the content of sodium ions in roots increased significantly. Further analysis showed that endogenous manganese (Mn) promoted K absorption concentration increase from 22.09 to 38.28 g/kg. Moreover, Joint and chemical remediation with Bc, HA, M and Bc + HA reduced Na to 5854.76, 9396.19, 6530.95 and 11164.29 g/(kg DW⋅m·a), respectively. Tests revealed that for , the aboveground biomass and root morphological plasticity, as well as the synergistic effect of K on Na transport capacity influenced by endogenous Mn in leaves, were the primary causes of the efficient improvement of saline-alkali land.