By controlling the interaction between cationic surfactant micelles and ammonium metatungstate during the formation of mesoporous silica structure, highly dispersed tungsten carbide (WC) nanoparticles of 2.0 nm in diameter on mesoporous silica nanospheres were synthesized at lower concentration of ammonium metatungstate. With additional ammonium metatungstate, a novel mesoporous silica nanobamboo structure was formed with bimodal size-distributed WC nanoparticles, in which 2.0 nm WC was homogeneously distributed in nanobamboo's mesoporous silica wall and those with larger diameter (10.0–20.0 nm) were only formed on the nanobamboo's inner surface and at its internodes. The mesoporous silica nanobamboo also had a very high tensile strength due to its bamboo-like structure.