The natural zeolite green color (GCNZ) from Ende-Flores, Indonesia has been activated with several acid solution series, characterized by XRF spectroscopy and used for methylene blue (MB) adsorption from aqueous solution. The characteristic of XRF showed that the natural zeolite has mainly composed of mordenite with Si/Al ratio of GCNZ before and after acid activated is 7.34 % and 16.28 % respectively. Surface area study was found out using the methylene blue adsorption method whereas adsorption process was done by the batch system. It was shown that average of surface area for GCNZ and activated green color natural zeolite (AGCNZ) is 49.069 m 2 /mol and 265.946 m 2 /mol respectively. The maximum adsorption capacity of MB onto the surface of GCNZ is 42.441 mg/g whereas AGCNZ is 87.592 mg/g. Kinetic modeling studies showed the adsorption process fits with pseudo-first-order rate mechanism. Isotherm studies show that adsorption process is best to describe by Freundlich isotherm model. Also, the thermodynamic process indicates that adsorption is an exothermic process and spontaneous.