<p>The crystallisation behaviour of carbon fiber reinforced polyetheretherketone composite (CF/PEEK) is affected by temperature changes during moulding and reprocessing, which ultimately affects their mechanical properties. Current studies do not consider the comprehensive effects of maximum temperature and cooling rate on crystallinity, and they lack prediction models. Therefore, the crystallinity and tensile properties of PEEK under different temperatures and cooling rates were obtained through DSC tests and quasi-static tensile tests, respectively. The influence of processing parameters on crystallisation and mechanical properties was also analysed. In addition, mathematical models for predicting the crystallinity and mechanical properties of PEEK and CF/PEEK were established, and the accuracy of the models was verified by a series of experiments. The results showed that the maximum temperature close to the melting point and the lowest cooling rate resulted in higher crystallinity, optimal mechanical properties and energy-saving. Under the same processing parameters, the crystallinity of the composite was approximately 1.07 times higher than that of the resin. The error of all theoretical calculated values from the prediction models falls within 11.03%, and the crystallinity of the resin can be directly used to predict the mechanical properties of the composites.</p>