The invention discloses a low-voltage capacitor element replacing device for a 500kV transformer station, and the device comprises a traveling mechanism and a suspension mechanism. The traveling mechanism comprises a cuboid frame and a guide rail, and the guide rail is provided with an electric block. The suspension mechanism comprises front suspension assemblies and rear suspension assemblies, wherein the front and rear suspension assemblies are located at two ends of the traveling mechanism. There are two groups of front suspension assemblies, and each group of front suspension assemblies comprise a front upper clamping part, a front lower clamping part, and a front threaded suspension rod, wherein the front threaded suspension rod enables the upper end of the cuboid frame to be fixed with a capacitor platform frame. There are two groups of rear suspension assemblies, and each group of rear suspension assemblies comprise a rear upper clamping part, a rear lower clamping part, and a rear threaded suspension rod, wherein the rear threaded suspension rod enables the lower end of the cuboid frame to be fixed with the capacitor platform frame, and the front end of the cuboid frame stretches out of the capacitor platform frame. The device is provided with the traveling mechanism and the suspension mechanism, effectively simplifies the operation process, and reduces the workload. Moreover, an extending board is provided with through holes in different shapes, thereby achieving the suspension of the device exactly above a capacitor, and facilitating the quick operation.