The invention discloses a wide-grain-grade double-dense-medium process for separating all coarse coal slime. The wide-grain-grade double-dense-medium process includes that raw coal is preliminarily sieved, manually picked and graded, then oversize products can be used as coarse grain coal, the coarse grain coal is fed into a non-pressure tri-product dense-medium cyclone to be separated, undersize products are concentrated and graded and then are dehydrated in an underflow manner to be used as fine grain coal, the fine grain coal is fed into a pressure tri-product dense-medium cyclone to be separated, and excess flow is fed into a flotation filter-press system, so that the coal slime can be separated; qualified suspension liquid of a fine grain coal dense-medium separating system is provided by coarse grain clean coal of a coarse grain coal separating system, lower branches of coarse grain middling coal primary-section medium removing equipment and branches of coarse grain clean coal and coarse grain middling coal magnetic separation concentration; dilute suspension liquid of coarse grain gangue products and dilute suspension liquid of middling coal and gangue products of a fine grain coal system are treated together; magnetic separation tailings are used as wetting water or primary spray water for grading screens. The wide-grain-grade double-dense-medium process has the advantages that the fine grain coal dense-medium system has a medium automatic generating function, all the coarse coal slime can be efficiently separated by dense media, the suspension liquid is circulated in a closed-loop manner, the separation efficiency is high, the products are flexible in structure, and the production and operation costs are low.