In　this　study,　we　synthesized　pH-sensitive　thiamethoxam-3-(2-aminoethylamino)　propyl-bimodal　mesoporous　silica　(P/Thi-NN-BMMs)　nanoparticles　(NPs).　We　used　this　bimodal　mesoporous　silica　(BMMs)　mesoporous　material　as　a　carrier　based　on　the　principle　of　free　radical　polymerization.　The　size　of　the　P/Thi-NN-BMMs　NPs　was　about　891.7　±　4.9　nm,　with　a　zeta　potential　of　about　-25.7　±　2.5　mV.　X-ray　powder　diffraction　analysis,　N2-sorption　measurements　and　thermogravimetric　analysis　indicated　that　thiamethoxam　(Thi)　was　loaded　into　the　pores　of　the　mesoporous　structure　and　that　the　mesopore　surface　was　coated　with　polyacrylic　acid　(PAA).　The　loading　rate　of　P/Thi-NN-BMMs　was　about　25.2%.　The　controlled-release　NPs　had　excellent　anti-photolysis　performance　and　storage　stability.　The　NPs　showed　significant　pH　sensitivity,　and　the　Thi　release　rate　in　pH　10.0　phosphate　buffer　was　higher　than　those　in　pH　7.4　and　pH　3.0　phosphate　buffers.　We　described　the　sustained-release　curves　according　to　the　Weibull　model.　The　relative　toxicity　of　P/Thi-NN-BMMs　against　peach　aphid　was　1.44　times　that　of　commercial　Thi.　This　provides　a　promising　instrument　for　effective　insect　control　and　environment　protection.