The invention discloses an LED street lamp with a sealing structure, and relates to the technical field of street lamps, the LED street lamp comprises a lamp pole, a mounting frame is arranged at the top of the lamp pole, a lamp body is arranged on the mounting frame, a water collecting box is arranged at the top of the mounting frame, a dustproof net is arranged at the top of the water collecting box, and a sealing cover is arranged at the top of the lamp body. A sealing groove is formed in the sealing cover, the sealing cover is clamped to the top of the lamp body through the sealing groove, the heat dissipation groove is communicated with the interior of the heat dissipation box, the rotating directions of the two sets of rotating fans are opposite, the heat dissipation groove and the heat dissipation box form a heat dissipation channel of the lamp body, and a guide rail and a fixing frame are arranged in the mounting frame. The fixing frame makes contact with the top of the sealing cover, a plurality of sliding blocks are arranged in the guide rail in a sliding mode, the sealing cover seals the lamp body below, rainwater and dust are effectively prevented from invading, when the interior of the lamp body is overheated, the sealing cover can be automatically jacked open, the fan is started, an efficient heat dissipation channel is formed, and the heat dissipation efficiency of the interior of the lamp body is guaranteed.