A method for carrying out grouting between adjacent gateroads in internal-staggered split-level coal mining. A return air gateroad of a stoping face and an inlet air gateroad of a heading face are not on the same level. The return air gateroad of the stoping face is arranged along a roof of a coal seam. The inlet air gateroad of the heading face is arranged along a floor of the coal seam. There is a height difference between the return air gateroad and the inlet air gateroad in a vertical direction. During the construction process, the inlet air gateroad is excavated at a delay distance of 180-200 meters from the return air gateroad. The drilling and grouting are performed while excavating the roadway, where grouting holes are arranged in a single row. A device for implementing the method is also provided.