Abstract: AIM　To prepare lung targeted tetrandrine (TET) loaded sustained-release drug delivery system by microencapsulation, decrease the toxicity and enhance the therapeutic function of anti-pulmonary hypertension of TET. METHODS　Albumin microcapsules were produced by spray drying-thermal denaturation, a new technique. Some characterization of the prepared microcapsules was evaluated. Distribution of the microcapsules and their anti-pulmonary hypertension effect in vivo were investigated. RESULTS　The spherical microcapsules showed a drug loading of 37.88%. Compared to the original drug, the rate of TET released from the positively charged microcapsules in vitro was significantly decreased and fitted well by Higuchi equation. The TET concentrations in mouse lungs of TET microcapsules were significantly higher than those of TET injection, and the mean retained time of TET in lungs was prolonged from 157.1 h to 223.6 h after microencapsulation. The in vitro - in vivo correlation was established and confirmed (P＜0.001). CONCLUSION　The new spray drying-thermal denaturation method allows the preparation of drug loaded albumin microcapsules with desired results. The prepared microcapsules were found to have the potential function of delivering TET to pulmonary artery via iv, with low toxicity and high efficacy.