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In order to solve the problem of high viscosity of high solid content propellants, supercritical carbon dioxide (SC‑CO2) has been used as a plasticizer to improve its rheological behavior. The in‑line viscosity of the CA/CaCO3 solution was measured by a slit die rheometer during the extrusion process assisted with SC‑CO2, and the Power law was used to describe the rheological behavior of CA/CaCO3 and CA/CaCO3/SC‑CO2 solutions. Polyflow was utilized to model the dispersive mixing properties of the CA/CaCO3/SC‑CO2 solutions. Results show that with the presence of SC‑CO2, the viscosity and pressure of the CA/CaCO3 solution decreases significantly.And the viscosity coefficient of the CA/CaCO3 solution at 50℃ decreases by 26.00%, while its non‑Newtonian index increases by approximately 16.67%. As the extrusion temperature increases, the viscosity of the CA/CaCO3/SC‑CO2 solution decreases, and its shear viscosity is less sensitive to temperature at higher shear rate. According to this simulation results, when the CA/CaCO3/SC‑CO2 solution is subjected to the maximum shear stress, the maximum probability density increases by 20.63% at 50 ℃, which confirms that SC‑CO2 improves the dispersion mixing properties of the CA/CaCO3 solution.“,”为了改善高固含量发射药挤出加工时流变性能，采用超临界二氧化碳（SC‑CO2）作为增塑剂辅助高固含量发射药代料醋酸纤维素/碳酸钙（CA/CaCO3）挤出加工，通过狭缝流变仪和幂律方程研究了CA/CaCO3和CA/CaCO3/SC‑CO2溶液的在线流变行为，使用Polyflow软件模拟了CA/CaCO3/SC‑CO2溶液的分散混合性能。结果表明，温度为50 ℃时，SC‑CO2使CA/CaCO3溶液的稠度系数降低了26.00%，非牛顿指数增加了16.67%，降低了CA/CaCO3溶液在挤出过程的粘度和压力；随着加工温度的升高，CA/CaCO3/SC‑CO2溶液的粘度降低；在低剪切速率下，CA/CaCO3/SC‑CO2溶液的剪切粘度对温度的敏感性较高；根据模拟结果，温度为50 ℃时，CA/CaCO3/SC‑CO2溶液经受最大剪切应力的最大概率密度比CA/CaCO3溶液增加了20.63%，SC‑CO2的注入有利于CA/CaCO3溶液分散混合性能的提高。