Kitchen waste mixed-base biochar (KW600, KW800, KW1000) was made of eggshell, banana peel, tea residue, cabbage and leftover rice. It was prepared by high temperature with common heat. The pH of the solution was in the range of 410, KW600, KW800 and KW1000 all had good Malachite green adsorption effects, and the maximum adsorption amounts were 235mg/g, 2969 mg/g, 7434 mg/g, respectively. The adsorption process is in accord with pseudo-second order kinetics, Elovich, intraparticle diffusion and Langmuir-Freundlich model fitting.