Abstract: OBJECTIVE To explore the miscibility of tanshinone IIA(Tan-IIA) with different immediate-release excipients and to evaluate the influences on glass transition temperature(Tg) values of the excipients by Tan-IIA. METHODS Binary solid solution consisting by different types and ratios of immediate-release excipient/Tan-IIA were prepared by solvent method. Then the Tg of the solid solutions was measured by differential scanning calorimetry. RESULTS Tan-IIA had good miscibility with the three types of immediate-release excipients, and the Tg values of the binary solid solution with different types and ratios of excipients could be influenced with different degrees through anti-plasticizing effect of excipients and/or the molecular force between excipients and drug. CONCLUSION This study can provide technical support for the preparation of Tan-IIA loaded immediate-release amorphous drug delivery system using HPMC K4M, Kollidon VA64 or Soluplus as excipients.