用ＤＳＣ，ＤＭＴＡ研究了醋酸纤维素（ＣＤＡ），聚乙烯基吮咯烷酮（ＰＶＰ）及ＣＤＡ／ＰＶＰ共混体系的玻璃化转变行为．用精密量热法测定了该体系的混合热焓．结果表明：共混体系只存在一个玻璃化转变温度（Ｔｇ），其值随共混组成的变化而改变；共混体系的混合热焓为负值，其绝对值随组成中ＰＶＰ含量的增加而减少．力学性能研究表明，共混体系具有协同效应．上述试验结果证明，ＣＤＡ和ＰＶＰ是一对相容性高聚物． The glass transition behavior of cellulose acetate (CDA), polyvinylpyrrolidone (PVP) and CDA / PVP blends was studied by DSC and DMTA. The enthalpy of mixing of the system was measured by the calorimetry. The results show that there is only one glass transition temperature (Tg) in the blends, and its value changes with the composition of the blend. The enthalpy of mixing in the blends is negative, and its absolute value increases with the increase of PVP content cut back. Mechanical properties studies show that blends have a synergistic effect. The above test results show that, CDA and PVP is a pair of compatible polymers.