We propose an alternative solution to plastic from petrochemical origin, with biodegradable and compostable plastic, which comes from waste paper. We present a new method of recovering waste paper to obtain cellulose acetate. The composition of papers is more than 80% of cellulose. Our objective is the recovery of cellulose by synthesizing a derivative that is cellulose acetate derivative with high degree of substitution via direct acetylation using acetic anhydride. So the optimization of experimental parameters influencing the acetylation reaction (temperature, reaction time, report (acetic acid / cellulose anhydride) were conducted. The cellulose of waste paper was treated with acetic anhydride and catalytic amount of sulfuric acid to obtain cellulose acetate. The results confirmed the identity with literature.