As　a　natural　preservative,　cinnamaldehyde　(CA)　has　a　bright　application　prospect.　However,　CA　is　sensitive　to　light　and　can　be　easily　oxidized.　What＇s　more,　its　water　solubility　is　poor.　These　properties　greatly　limit　its　application.　In　this　study,　CA/sodium　alginate　(SA)/chitosan　(CS)　nanoparticles　(CA/SA/CS　NPs)　were　prepared　by　using　SA　and　CS　as　wall　materials,　and　CA　as　core　material.　The　single　factor　experiment　showed　that　the　optimal　CA/SA/CS　NPs　can　be　obtained　when　the　mass　ratio　of　SA　to　CS　was　5.5/1,　SA　to　CaCl2　was　5/1,　SA　to　CA　was　1/2,　and　the　pH　of　CS　solution　was　5.0.　Under　this　condition,　the　average　size　of　the　prepared　nano-particles　was　455.2　nm,　polymer　dispersity　index　(PDI)　value　was　0.189,　zeta　potential　was　-40.8　mV,　and　the　encapsulation　efficiency　was　72.92%.　The　scanning　electron　microscopy　(SEM)　and　atomic　force　microscopy　(AFM)　images　confirmed　the　formation　of　nanoparticles,　which　were　spherical　or　ellipsoidal　in　shape.　The　fourier　transform　infrared　spectroscopy　(FTIR)　and　multifunctional　polycrystalline　X-ray　diffraction　(XRD)　spectra　indicated　that　CA　was　encapsulated　in　the　nanoparticles.　Furthermore,　in　vitro　release　experiments　showed　that　CA/SA/CS　NPs　had　the　function　of　sustained　release.　In　summary,　SA/CS　NPs　can　be　used　as　a　promising　carrier　for　CA.