Drug-loading hydrogels were prepared from O-carboxymethyl chitosan (O-CMCS) with a high degree of substitution and different deacetylation degree (DD) using acetylsalicylic acid as drug and glutaraldehyde as a cross-linking agent. Also, the DD’s effect on the controlled drug release performance of drug-loading particle was explored. The results showed that the hydrogels and particles were prepared from 5 g of O-CMCS solution (4.0 wt.%), 2.5 g of sodium acetylsalicylate solution (8.0 wt.%), and 1.5 mL of glutaraldehyde solution (1.0 wt.%). The interior pore size of the particle (DD = 51%) was between 50 and 100µm, and its cumulative drug release ratios in the simulated gastric and intestinal juices were of the top values. The drug release of the drug-loading particle was proved to be obviously pH sensitive and it can be applied as a colonic drug.