The invention relates to a mobile robot mechanism, in particular to an insulator detecting robot mechanism. The insulator detecting robot mechanism comprises an upper platform, a lower platform, a first branch chain, a second branch chain, a third branch chain, an upper clamping jaw, a lower clamping jaw and a detecting mechanism, wherein the upper platform and the lower platform are connected with each other through the first branch chain, the second branch chain and the third branch chain; the upper clamping jaw and the lower clamping jaw are arranged on the upper platform and the lower platform respectively; and the detecting mechanism is arranged on the upper platform, the lower platform, the first branch chain, the second branch chain or the third branch chain. The first branch chain, the second branch chain and the third branch chain are identical in structure. Each branch chain comprises an upper connecting rod, a first lower connecting rod and a second lower connecting rod, wherein the upper end of the upper connecting rod is connected with a first rotating joint horizontally arranged on the upper platform; the lower end of the upper connecting rod is hinged with one end of the first lower connecting rod and one end of the second lower connecting rod respectively; and the other end of the first lower connecting rod and the other end of the second lower connecting rod are hinged to the lower platform. The insulator detecting robot mechanism provided by the invention has the characteristics of stable movement, good adaptability, high load capacity and the like.