The invention discloses an all-directional adaptive flexible connecting mechanism for a mobile robot and a detecting system. The connecting mechanism comprises a first connecting base and a second connecting base, wherein an elastic element, a central shaft, a vertical direction adjusting mechanism and a horizontal direction adjusting mechanism are successively arranged between the first connecting base and the second connecting base; one end of the elastic element is arranged on the first connecting base in a sleeving manner; the other end of the elastic element is in contact with one side of the central shaft; the vertical direction adjusting mechanism is connected with the central shaft; the horizontal direction adjusting mechanism is connected with the vertical direction adjusting mechanism so that movement of the central shaft in the vertical direction and the horizontal direction is realized; and the other side of the central shaft is connected with the second connecting base. While used for ultra-high frequency detection, the all-directional adaptive flexible connecting mechanism is also suitable for places requiring automatic alignment under the conditions that the plane of the tail end of a mechanical arm cannot be parallel to an operation plane in other industrial automated situations.