The invention relates to an ultrasonic welding device used for a solar energy collecting panel and provided with a welding mark coating mechanism. The ultrasonic welding device is provided with a base platform, wherein a rack is arranged on the base platform, the rack is provided with one set of ultrasonic welding machines at least, rails and transmission pairs, the ultrasonic welding machines can do parallel linear motion and vertical up-and-down motion on the rails, a compression mechanism for the collecting panel when the collecting panel is welded is arranged on the rack, a clamping mechanism for clamping a collecting rack piped or a collecting component welded with the collecting panel is arranged on the base platform, and motors for driving the welding machines to move, driving the clamping mechanism to clamp and driving the compression mechanism to perform operating movement, pressure and/or hydraulic mechanisms and a controllers are arranged on the base platform and the rack. The ultrasonic welding device is characterized in that the ultrasonic welding device is provided with one set of coating mechanism for coating resin on a welding mark at least. The ultrasonic welding device has the advantages that the coating is accurate, the production is stable and reliable, and the efficiency is high.