Abstract: In this article, the complex process of phthalocyanine nickel with Fe₃O₄ nanoparticles has been analyzed, the complex mechanism and the structure model for NiPc-Fe₃O₄ nanoparticles composite have been studied. For the complexes mechanism of NiPc with Fe₃O₄ nanoparticles, first, there are complex between NiPc and all Fe₃O₄ nanoparticles. Then, Fe₃O₄ nanoparticles accumulate together to form the accumulators; NiPc have the function of cohering Fe₃O₄ nanoparticles. A considerable number of NiPc combine with Fe₃O₄ nanoparticles and on the surface of the accumulators to form NiPc-Fe₃O₄ nanoparticles composite. All the processes above take place spontaneously. Inside the NiPc-Fe₃O₄ nanoparticles complex, Fe₃O₄ nanoparticles accumulate together without order, on the surface of composite, NiPc form a molecular dispersion layer. The threshold of the molecular dispersion layer is 0.06 g/g(Fe₃O₄).