Nowadays dyes has been used in textile industry but even at low concentration, it is highly visible and undesirable. Petai Belalang biomass can be another alternatives that can be utilized as new non-conventional and low cost adsorbent for the removal of dyes which is Malachite green. This batch adsorption studies was carried out for findings the optimum condition which are concentration of adsorbate solutions, temperature, contact of time, adsorbent dosage, pH and the particle size of adsorbent. For the isothermic studies, Langmuir and Freundlich model were applied to analyze the equilibrium data at different temperature. The best fitting isotherm models was found to be Langmuir rather than Freundlich. This indicates that the monolayer adsorption was take place where the maximum capacity of Petai Belalang for Malachite green ion was found to be 196.08 mg/g at 30°C.