Silane coupling agents of KH550, KH560, and KH570 were employed for surface modification of silicon carbide whiskers (SiCw), and their effects on the hardness, flexural strength, and friction and wear performance of SiCw/polyimide (PI) composites were investigated. The results show that surface modification with KH550 and KH560 can effectively enhance the hardness and flexural strength of the composites, with KH560 showing more pronounced improvements. However, KH570 modification led to a notable reduction in hardness and flexural strength of the composites. When subjected to abrasion against GCr15 balls at loads ranging of 6~12 N, the surface modification with KH550 and KH560 significantly improves the wear resistance of the composites. Specifically, at lower loads (6 N) during abrasion, the KH560-modified composites exhibits the lowest wear rate, but as the friction load increases, the wear rate rises rapidly. Under higher loads of 9~12 N, the KH550-modified composites possesses the best wear resistance among all comparative samples. However, the wear resistance performance of KH570-modified samples is consistently poor under various loads, indicating that KH570 is not suitable for surface modification of SiCw in SiCw/PI composites.