The invention discloses a composite insulator and vulcanized silicone rubber hydrophobicity detector based on a multi-rotor unmanned aerial vehicle. The detector comprises a walking mechanism and a machine frame connected with the lower side of the walking mechanism through a mechanical arm. The walking mechanism comprises a rear walking wheel clamped to the rear portion of a transmission and transformation line and a front walking wheel clamped to the front portion of the transmission and transformation line, the machine frame is provided with a graph collection mechanism, a water spraying mechanism, a drying mechanism and a spray coating mechanism, the machine frame is provided with a wireless controller, and a lifting mechanism is arranged on the upper portion of the walking mechanism. By means of cooperative action between the lifting mechanism and other mechanisms, a detection device can be easily hung to the high-altitude transmission and transformation line, and the detection device can continuously work on the transmission and transformation line through the walking mechanism; besides, after spraying detection, defects can be removed through the drying mechanism and the spray coating mechanism, the phenomenon that accumulated water is likely to be generated on the detector, a large amount of adhesive water still appears on the detector and accordingly ice blocks are generated on rainy and snowy days, and the detector is worthy of application and popularization.