The drug release characteristics of Da Chuanxiong Fang multiunit drug delivery system (DCXFMDDS) in vivo and in vitro were evaluated.  Ferulic acid (FA) and senkyunolide I (SI) were used as marker components, which were two of the effective components of Da Chuanxiong Fang.  And their contents were determined by HPLC.  Drug release characteristics in vitro of DCXFMDDS and Da Chuanxiong pills and pharmacokinetics characteristics of DCXFMDDS and Da Chuanxiong Fang active fraction (DCXFAF) in rats were compared.  It was obvious that FA released from the DCXFMDDS in a sustained fashion but SI in a fast fashion both in vitro and in vivo.  The releasing process and the releasing mechanism of FA and SI from DCXFMDDS were different, but the AUC value indicated that compared with DCXFAF the extent of absorption of FA and SI from DCXFMDDS was increased.  Though from the same multiunit drug delivery system, FA an SI had different drug release characteristics both in vitro and in vivo, and that may be one of the reason why DCXFMDDS has the good properties such as rapid and long-lasting effect and high efficiency.