Recently,　the　use　of　nanomaterials　(i.e.,　Nano-Silica　(NS)　and　Nano-SiC(NC))　to　improve　the　mechanical　properties　and　durability　performances　of　cement-based　materials　has　received　considerable　attention.　This　work　presents　the　effects　of　nanoparticles　(NS),　the　specimen　size,　and　the　water-reducing　agent　on　the　antipullout　strength　between　the　reinforcement　and　cement　mortar　on　the　basis　of　the　laboratory　antipullout　tests.　The　mechanism　is,　then,　validated　by　the　microscopic　analysis　with　Scanning　Electron　Microscopy　(SEM).　Results　show　that　NS　can　accelerate　the　hydration　reaction　of　cement,　produce　more　Calcium　Silicate　Hydrate　(CSH)　gel,　and　increase　the　density　of　the　cement　mortar,　thereby　improving　the　microstructure　and　antipullout　strength.　The　moderate　NS　(1.0%)　is　recommended　to　improve　antipullout　between　the　reinforcement　and　cement　mortar.　Besides,　the　specimen　size　and　water-reducing　agent　have　an　obvious　influence　on　the　antipullout　strength.　These　results　would　provide　guidance　on　the　design　or　construction　of　the　cement　mortar　with　reinforcement.