A double-layer quick coal cutting device comprises a transmission cabinet. An explosion-proof motor is arranged in the transmission cabinet. The output end of the explosion-proof motor is connected to a speed change mechanism. The output end of the speed change mechanism is provided with a first shaft. A first chain wheel is fixed to the first shaft. A second chain wheel is arranged on one side of the first chain wheel. The first chain wheel and the second chain wheel are sleeved with a long cutting tooth chain. The long cutting tooth chain is engaged with the first chain wheel and the second chain wheel. The second chain wheel is fixed to a second shaft. A third chain wheel is further fixed to the second shaft. The second chain wheel and the third chain wheel are arranged in a spaced mode. The third chain wheel is sleeved with a short cutting tooth chain parallel to the long cutting tooth chain. One end of the short cutting tooth chain is connected to the third chain wheel in a sleeving mode, and the other end of the short cutting tooth chain is connected to a fourth chain wheel in a sleeving mode. The short cutting tooth chain is engaged with the third chain wheel and the fourth chain wheel. Cutting teeth are arranged on the periphery or peripheries of the long cutting tooth chain or/and the short cutting tooth chain. By adoption of the long cutting tooth chain and the short cutting tooth chain, double-layer coal cutting can be achieved, the coal cutting efficiency is improved, and inclined thin coal seams and comprehensive coal rock can be flexibly cut.