Abstract: Volatile component can reflect viscosity and fluidity of matrix material，which is an important quality index of carbon fiber prepreg samples.And the measurement of the content of volatile component is critical，which confines the moulding process of composite and the end use of product.Volatile component of different carbon fiber prepreg samples were determined on different conditions.Tests were performed in ovens with the blower on or off and with weighing dishes of different diameters.According to the results of tests，effects of measurement on determination of volatile component in cyanate ester resin prepreg samples are investigated.Volatile component of carbon fiber prepreg samples is more in ovens with the blower on than with the blower off，and what's more the less volatile component，the bigger weighing dishes of different diameters.