Maleic anhydride-grafted polysulfone (PSF-g-MAH) was prepared by copolymerization in a solution. Compared to polysulfone, the surface tension and its polar fraction of PSF-g-MAH were increased by modification. The PSF-g-MAH was used to compatibilize polysulfone (PSF)/thermotropic liquid crystalline polymer (TLCP) (Vectra B950) blends. DRS-FTIR investigations showed that the special interaction between PSF and TLCP phases was enhanced due to the incorporation of PSF-g-NLAH. The X-ray photoelectron spectroscopy (XPS) and PLM studies revealed that some chemical reactions had occurred between PSF-g-MAH and TLCP components, which produced PSF-VB copolymers. It is suggested that the improvement of compatibility should be attributed to some interactions including both chemical and physical ones. The improvement of compatibility was also confirmed by DMA and TGA analysis. Morphological observation showed that the addition of compatibilizer significantly reduced the size of the dispersed TLCP phase, and in case of injection molding, PSF-g-NLAH promoted the TLCP fibrillation and improved their dispersion within the matrix. The processabilities of PSF/TLCP blends before and after compatibilization were investigated. It was found that the melt viscosities were increased by the addition of PSF-g-MAH, which also gave an evidence of the occurrence of interaction between phases.