Formaldehyde is found in resins used in the manufacture of composite wood products such as wardrobes, household products such as glues, permanent press fabrics, paints and coatings, lacquers and finishes, and paper products. Formaldehyde may cause eyes, trachea, and skin irritation. High levels of exposure to formaldehyde may cause myeloid leukemia and cancers. In this study, chitosan gel is prepared by dissolving in vinegar and used to remove formaldehyde by breaking down it into harmless substances, such as water. In the experiment, the effect of 0.1g-0.5g of chitosan gel on formaldehyde removal are tested. The concentration of chitosan for achieving the optimal efficiency was 0.2g per 10 mL of vinegar. The efficiency of the chitosan gel was also compared with commercial products including ion air purifier, 3M, charcoal powder and charcoal beads. Chitosan gel was found as the most effective among all products and removed the highest amount of formaldehyde (-99.04%). The gel was found to be reusable with similar efficiency. To summarize, our chitosan gel was found to be a low-cost and eco-friendly product with high removal efficiency.