An approach for the preparation of tetrandrine sustained release calcium alginate gel beads was described. In vitro the release of tetrandrine from sustained release dosage forms went on a time of 12 hours which fitted non-Fickian diffusion with matrix erosion significantly. In vivo the plasma concentration of tetrandrine extended preparation given in dogs reached C_max 2.67±0.69 μg/ml approximately at 5.67±0.58 h after oral administration. The AUC_0→24 and AUC_0→∞ were 24.64±6.77 mg·h/l and 29.75±5.30 mg·h/l, respectively. The elimination half-time was 9.6±2.40 h. While a favorable correlativity existed between in vitro and in vivo with a correlative coefficient of 0.9798 through linear regression. An investigation on the quantitative relationship between in vitro release and in vivo absorption is a highly necessary work guided for manufacture, optimization and in vivo evaluation of sustained release dosage by means of in vitro release or dissolution tests.