Abstract: High-performance thermoplastic plates are widely used in automobiles, electrical appliances, medicine, building materials and so on. Some functional elements, such as Ti and Sb, are often added to improve their performance. How to detect its composition and contents quickly is very important for the study of thermoplastic plates. The morphology and composition of high-performance thermoplastic plates has been analyzed by scanning electron microscopy and energy dispersive spectrometry (SEM/EDS), the effects of conductive treatment on the morphology and composition have been studied respectively. The thermodynamic characteristics of high-performance thermoplastic plates were analyzed by the thermal analysis technology. The results showed that the high-performance thermoplastic plate without a conductive treatment was decomposed and sublimated during the EDS analysis, and the functional elements disappeared, so its composition and content cannot be accurately detected. A proper conductive treatment in the EDS analysis of high-performance thermoplastic plate provides a method and guidance for its accurate detection.