In order to increase the working efficiency, improve the design quality of transmission and transformation engineering design, and optimize the design scheme, an intelligent design platform is proposed. The new idea of constructing the proposed platform is explicitly demonstrated in four aspects: the construction principles, the overall structure, the key issues, and the operation modes. The proposed key measures can solve the problems of building up a cloud database of the intelligent design platform by means of constructing an object-based management platform of heterogeneous data, extracting and structuring cloud database text information. A dynamic collaboration management strategy based on a network diagram is introduced to solve the issues of building up multi-task paralleling and a multi-profession-collaborating management system. Modularizing design and the intellectualizing evaluation are introduced to solve the key problems of developing periodically, expanding and upgrading the intelligent-design-terminal, and the evaluation is integrated in the design process. The intelligent design platform for power transmission and transformation engineering provides a feasible way to achieve a leapfrog from the current artificial design mode to the intelligent design mode. This work is supported by National Natural Science Foundation of China (No. 51607075).