The invention discloses a double compensation flexible sealing brush plate for air preheater, and relates to the technical field of an air-sealing device. The key technology of organic combined double compensation of dynamic coarse adjustment and micro adjustment is adopted. The upper end section of a flexible plate is connected with the lower end of a brush cover in a riveting manner; the upper end section of the brush cover is connected with a sealing brush in an inlaying manner; the lower end of the flexible plate is fixedly connected with a rotor of the air preheater through a fixed hole.The thickness of the flexible plate is 0.5-3mm, the bending angle is 15-30 degrees and the thickness of the sealing brush is 1-4mm. The flexible sealing brush plate is used for air sealing of a rotary air preheater. The double compensation flexible sealing has simple and ingenious design, easy manufacture, low cost and stable effect, reduces air loss of a furnace, increases efficiency of the furnace, improves fuel ignition and burning condition, saves fuel energy sources, reduces environmental pollution, lowers electricity consumption of induced draft fans, forced fans or primary air fans andimproves comprehensive economic benefit.