Abstract: A reliable and safe trailer frame has been designed to address issue of cracking during movement of frame of a rural toilet manure treatment machine trailer．Longitudinal beams, transverse beams, and auxiliary support beams of full trailer frame with a load capacity of 8 tons were designed using Solidworks software, and simulation analysis was conducted through 3D modeling．At the same time, simplified longitudinal beam of full trailer frame was subjected to determination of dangerous section of frame and strength verification, and displacement and stress verification of full trailer frame were carried out．Based on force analysis and calculation results, structural optimization and improvement were carried out to ensure that parameters of entire vehicle frame were within a safe range, ultimately completing overall frame structure design．A rural toilet manure treatment machine experiment was carried out with a treatment capacity of 3.1 m³/h．After treatment, pH value of manure water was 6.55, BOD was reduced by 91%, COD was reduced by 75.9%, ammonia nitrogen was reduced by 79.57%, and suspended solids were reduced by 99.65%．This achieved mechanized treatment of rural toilet manure nearby and on-site, laying foundation for resource utilization．