Taking 3-span and 6-span 220 kV truss-column frames as example, four types of commonly used substation frames are proposed and designed in this paper, and related finite element analyses are performed to study their force mechanism. The horizontal beam types and beam-to-column connections of different frames are investigated and compared. The research results indicated that, when beam and column is fix-connected, the usage of latticed angled beam is higher than tubular beam; when latticed tubular beam is used, the member usage of fixed frame is higher than pin-ended frame. The frame with pinned beam-to-column joints is flexible. Lastly, the reasonable 220 kV truss-column structure type is recommended, with latticed tubular beam, angle braces, and pin-ended beam-to-column joints.