In a method, a gyroscope and an endoscopic camera are first used to investigate coal-seam strike trend, coal-seam dip trend, and coal-seam thickness data of a to-be-extracted area. According to gas extraction standard requirements of a to-be-extracted area, boreholes are then designed and constructed, and trajectories of boreholes are tracked to obtain a correspondence relationship between designed borehole parameters and actual borehole trajectory parameters. Next, drilling parameters are adjusted according to the correspondence relationship between the designed borehole parameters and the actual borehole parameters to construct boreholes at predetermined borehole locations. Subsequently, the boreholes are connected to an extraction pipeline, and gas extraction flow rates and gas extraction amounts per meter of the boreholes are observed. Eventually, other boreholes are designed and constructed according to the adjusted borehole construction parameters and extraction data. After being constructed, the boreholes are connected to perform gas extraction.