Controlling the fluid behaviors of energetic suspensions is one of the crucial technologies for controlling the inner defects of munitions. Considering the lack work on energetic suspensions with nanoparticles, dissipative particle dynamics(DPD) simulation technology was used to investigate the influences of particle shape, size, content and gradation on the viscosity of energetic suspension systems in this paper. It shows that the influence of the particle shape can be neglected in the case of low contents. With the increase of the content of nanoparticles, the viscosity of the suspension rises accordingly. For a same amount of nanoparticles, the smaller the size, the greater the viscosity of the suspension. The addition of nanoparticles does not change the dependence of the system viscosity on the temperature. For the same content, the particle gradation of two different sizes of nanoparticles can effectively adjust the viscosity of the system. By introducing the solvation effect of nanoparticles, the traditional Einstein viscosity calculation formula is corrected to be more efficient. The particle size and content are both introduced to a model to effectively predict the viscosity of fluids ranging from nano-to micro-scale.