The invention relates to the technical field of a moving robot, in particularly relates to a travelling clamping device of a power transmission line inspection robot. The travelling clamping device can be used for effectively preventing the inspection robot from falling off and can be adaptive to angle change of a power transmission line to effectively prevent an obstacle when the obstacle is met.The travelling clamping device comprises a travelling mechanism, two variable-cell clamping mechanisms and a driving mechanism, wherein the travelling mechanism comprises a travelling wheel rack anda travelling wheel, the traveling wheel is rotatably supported on the travelling wheel rack, the two variable-cell clamping mechanisms are respectively arranged in front of and behind the travelling wheel, are fixed on the travelling wheel rack and can be switched between a clamping state at which the power transmission line is clamped and a loosen state at which the power transmission line is separated, the driving mechanism is used for driving the two variable-cell clamping mechanisms to be switched between the clamping state and the loosen state so that the states of the two variable-cell clamping mechanisms are synchronous, and the driving mechanism is fixed on the travelling wheel rack.