The composite propellant formulation is important to determine rocket performance. The composite propellant consists of an oxidizer, fuel, and binder. The widely utilized composite propellant is composed of Ammonium Perchlorate (AP) which serves as the oxidizer, and hydroxyl-terminated polybutadiene (HTPB) which functions as the binder and fuel, and aluminium powder that serves as the fuel. Besides being famous for their superior performance and low manufacturing costs, composite solid propellants containing AP and HTPB have the potential to be poisonous and detrimental to the environment. When AP-based composite propellants burn, they typically generate white smoke. Perchlorate contamination has become a growing concern in a number of countries throughout the world. The research conducted is to find the material and composition which can reduce HCl gas as a result as combustion with high specific impulse. The research uses the descriptive-analytic method, in which data was collected from literature studies. The data shows that the composition which AP include in it still has a high percentage of mol HCl. The composition without AP shows the best result in a percentage of mol HCl, the material of this composition is 2,2,2-trinitroethyl-formate (TNEF), Ammonium dinitramide (ADN). CL20 also show good result even in combination with Ammonium Perchlorate (AP), although the number of percentages is not 0% but still below compared with AP+RDX+HTPB or AP+Mg+HTPB. The best specific impulse was obtained by the composition of ADN+ETN+HTPB. This means a decrease in hazardous in the atmosphere can be done without reducing the performance of the propellant.