The stability of adsorbed heavy metals onto biochars is one of the most important factors to evaluate the biochar’s remediation performance. In this study, the effects of pH and coexisting ions Cd/Al on Pb desorption were investigated. It was found that Pb desorption increased with the decrease of pH which was mainly due to the competing effect of H⁺ and the protonation of functional groups which promoted the activation of Pb. However, with the presence of Cd/Al, the desorption efficiencies of Pb were further promoted. At pH 3.5, apromotion effect was observed from the presence of Cd, with Pb desorption efficiencies increasing by 13.9%, 1.0%, 3.4% for CM100, CM400 and ZKZ700, respectively; the increases were even stronger for Al at 26.8%, 13.0% and 11.3%. The more metal hydrolyzed, the more release of H⁺, which helped to activate more Pb from the surface of biochars. The desorption efficiencies of Pb increased with the increasing contact time. During the first 4 h, Pb was quickly desorbed from biochars to account for 70% of their maximum Pb desorption. However, the rate of Pb desorption gradually decreased during the next 20 hours. Desorption of Pb from biochars followed the pseudo-first order kinetic model and the intraparticle diffusion model during the first 4 h. The presence of Cd/Al and preferential desorption of these coexisting ions reduced Pb desorption rate and extended the time to reach equilibrium.