Reasonable particle size distribution is the key to improve the internal compactness， early mechanical strength and interfacial bonding ability of cementing cement sheath. Based on this， Dinger-Funk equation （hereinafter referred to as “DFE”） is selected to design cementing slurry system from several typical close packing theory of continuous particle gradation. Through a large number of experiments， the optimal range of n value suitable for the design of cement slurry for oil and gas wells is determined for the first time： 0.33~0.40. Combined with the measured results of laser particle size analyzer， nano CaCO₃ （hereinafter referred to as “NC”）， grade G oil well cement and floating beads are successively used in the three particle size ranges of ≤3.38μm， 3.38~70.70μm and ≥70.70μm， and mixed according to the volume distribution curve of DFE （n=0.33~0.40）. On this basis， a low-cost， low-temperature and early strength ternary solid-phase graded cement slurry with a density of 1.50g/cm³ was proposed， and its performance is compared with that of the floating bead binary cement slurry and NC binary cement slurry. The results show that： the compressive strength， flexural strength and interfacial bonding strength of the ternary system are increased by 7%~21.1%，13.4%~51.9% and 41.4%~122.2% respectively compared with the binary system of floating beads and NC. The maximum vertical density difference of cementing cement is 0.022g/cm³. The ternary system based on DFE has good rheology， stability and mechanical properties. DFE has certain guiding significance for guiding the design and application of multiple cementing cement slurry system， and can effectively improve the early strength and comprehensive performance of cementing cement under the premise of ensuring low density.