The invention discloses a brush, which consists of a slide groove, a transverse strip, a holding handle, a slide ball, a vertical rod, brush heads and suction discs. The brush is characterized in that the slide groove is formed in the transverse strip; the slide ball is arranged in the slide groove; the vertical rod is arranged on the slide ball; one brush head is arranged at each of two ends of the vertical rod; the holding handle is arranged in the middle part of the vertical rod; one suction disc is arranged at each of two ends of the back side of the transverse strip. In the use process, a user enables the two suction discs to be sucked onto a wall surface, so that the transverse strip is fixed on the wall surface; then, the holding handle is held by hand; the vertical rod leftwards and rightwards moves in the slide groove; in the moving process, the brush heads are used for brushing away dust and spider web on the wall surface; after the completion, the actions are repeated according to the actual conditions for cleaning other wall surfaces. The brush has the beneficial effects of simpledesign, reliability and durability; convenience and safety, and economy and practicability.