The invention discloses a multi-coal-seam slide sleeve isolating and separate layer fracturing device and a multi-coal-seam slide sleeve isolating and separate layer fracturing method. The multi-coal-seam slide sleeve isolating and separate layer fracturing device comprises a casing pipe arranged in an open hole and passing through multiple coal seams, and a plurality of screen pipe segments corresponding to the multiple coal seams in position are formed on the casing pipe. Capsular bags sleeve the screen pipe segments and are used for enabling the casing pipe and rock strata on two sides of the coal seams to form a capsular bag-type well cementation structure, each two adjacent capsular bags are communicated through a communication pipe, and one of the capsular bags is connected with a grouting system through a grouting pipe. A plurality of slide sleeves, as many as the screen pipe segments, are movably arranged in the casing pipe to block screen holes of the screen pipe segments, a traction inhaul cable and a drag inhaul cable are connected at the front ends and the back ends of the slide sleeves respectively, and the traction inhaul cable passes through a reversing component at the front end of the corresponding slide sleeve to return out of a pipe orifice. The multi-coal-seam slide sleeve isolating and separate layer fracturing method is used for separate layer fracturing based on the multi-coal-seam slide sleeve isolating and separate layer fracturing device. The multi-coal-seam slide sleeve isolating and separate layer fracturing device has the advantages of simple structure, good hole blocking effect and low manufacturing cost. The multi-coal-seam slide sleeve isolating and separate layer fracturing method has the advantages of high operability, high efficiency and good coal seam permeability improvement effect.