In this study, virgin and thermal aged PPS samples were prepared and tested using different techniques such as thermogravimetric analysis (TGA), coupled TGA–Fourier transform infrared spectroscopy (FTIR), and FTIR as well as optical microscopy. Some interesting research results can be summarized as follows: TGA results prove the PPS composite samples aged at 180 and 200°C have been degraded obviously during the aging period in oven. Moreover, accelerated aging leads to the degradation of PPS composite with the observation of increased thermal oxidation layer from outside to inside. There is a plateau standing at about 350 μm for the thermal oxidation layer at oxidation temperature of 200°C. Some thermal decomposition models are applied to clarify the degradation kinetics of PPS composite. According to the activation energy value, it appears degradation more easily at the beginning of the heating process in the atmosphere of oxygen than that of nitrogen. Moreover, the related products of PPS composites during pyrolysis are fully discussed with the combined analysis of TGA–FTIR techniques.