MEL-type pure-silica-zeolite has shown to be good low-dielectric-constant (low-k) material due to its intrinsically uniform pore size and distribution, high hydrophobicity, strong mechanical strength and chemical stability. Our group's previous work has used two-stage synthesis method to synthesize MEL nano-particle suspension to prepare spin-on film. With this method, both particle size and yield of zeolite suspension, which is related to the crystallinity, increase with respect to the synthesis time. While higher yield give the material lower k value, larger crystals will introduce new troubles in spin coating applications, such as bad smoothness, large mesopores, and electrical breakdown. In this study, two-stage synthesis has been modified into evaporation-assisted two-stage synthesis method by adding a solvent evaporation process between two synthesis stages. The prepared nanoparticles with this modified method had smaller particle size and the synthesis yield was held the same. The 60% solvent evaporated suspension showed the bi-modal particle size distribution and the primary nanoparticles around 14 nm stably exist in final suspension. Both increasing viscosity and repulsive forces among particles after evaporation were responsible for the decrease of particle size. The spin-on film prepared from evaporation-assisted two-stage synthesis suspension turned out to be less striation and had similar dielectric-constant value and mechanical property to the two-stage synthesis suspension film.