Green natural zeolite catalyst preparation characterization and acid catalytic performance Natural clinoptilolite zeolite CLIN was acidified by ammonium ion exchange followed by calcination and HCl treatment under soft conditions. The influence of the modification type and treatment conditions on the structure morphology and acidity was studied by XRD SEM FTIR ICP AES TG DSC ammonia TPD 1H 27Al and 29SI MAS NMR and N2 ads des. High temperature calcination of NH4 CLIN and concentrated acid has a more severe impact on the clinoptilolite structure. H CLIN catalysts are potential and active acid catalysts and synthesis structure porosity acidity activity relationship was found.<eng>