Tubular conjugated microporous polymers (CMPs) were synthesized by Pd(0)/Cu(I)-catalyzed Sonogashira–Hagihara cross-coupling polycondensation. Taking advantage of its unique tube-liked morphology as well as good chemical and physical properties, for the first time, tubular CMPs as fillers were used for the preparation of polymer composites with polymethyl methacrylate and polydimethylsiloxane as polymeric matrix using a simple solution method. The tensile fracture toughness of polymer composites was enhanced after addition of CMPs nanotubes with appropriate loading, which contributed to the good compatibility of the fillers to the polymer matrix on the micro level arising from the intrinsic surface superhydrophobicity of CMP-I nanotubes. Our study may provide guidance for the further development of CMPs nanotubes or CMPs nanofibers as fillers for fabrication of polymer composites.