This paper describes a new method for urban transmission network planning required by environmental protection. In the traditional transmission network planning， the quantitative environmental protection factors are directly counted in while considering the population factor to make the result more humanized and enforceable. The index system of environmental protection is composed of indices related to radiation， land occupation and environmental compatibility. The planning results of Shanghai power grid show that the new method can influence the planning scheme macroscopically and make it more environment-friendly.