The shortage of water resources has become a serious constraint to the sustainable development of the country’s economy and society. The environmentally friendly field sewage purification device is one of the effective ways to reduce water pollution and solve the water shortage problem. In this paper, the RBF-purification model is used as a calculation tool to study the economic feasibility of the environmentally friendly field sewage purification machinery and its equipment maintenance. The calculation results show that the distance benefit of field sewage purification is 13%. The benefit share of comprehensive economic benefit is the highest, 41%. The share of environmental benefits is 39%. The professionalism of the equipment users has the highest percentage of the problems that need to be maintained in the field wastewater purification equipment, at 54%. The percentage of equipment operation and management was 27%. The smallest percentage is for equipment maintenance with 19%.