Abstract: OBJECTIVE To prepare solid dispersions containing chitosan matrix with three dimensionally ordered 470 nm macroporous and nimodipine (3D-CS/NMDP), investigate the drug release, stability and pharmacokinetics. METHODS The solid dispersions were prepared by solvent evaporating method. The drug release behaviors of the 3D-CS/NMDP solid dispersions in artificial gastrointestinal fluid were examined by dissolution experiments. The chemical, crystal and dissolution stability was determined by X-ray diffraction method and dissolution method respectively. After orally administrating the 3D-CS/NMDP solid dispersions and commercial preparations, the plasma drug concentration of rat was measured. RESULTS The dissolution of the solid dispersion in pH 6.8 medium was largely higher than that in pH 1.2 and pH 4.5 medium. Drug release curve in gradient pH media expressed Ladder type. The crystallinity and dissolution of the solid dispersion hardly changed in test period. The 3D-CS/NMDP solid dispersions had 1.91 times AUC_{0-12 h} of commercial preparations, and possessed prolonged action. CONCLUSION The self-made 3D-CS/NMDP solid dispersions have good stability, can markedly improve the bioavailability in rat after oral administration.