The invention discloses a method for descending and suspending a production casing for a mining area ground coal-bed gas well. The method comprises a first step of welding a blocking block to the inner side of the lower end of a secondary casing; a second step of welding an annular hanging sleeve and a clamping block to the outer side of the upper end of the production casing; a third step of connecting the production casing and a drill rod through a thread connection structure; a fourth step of using the drill rod to descend the production casing, enabling the clamping block to be inserted in a side space of the blocking block, and placing the annular hanging sleeve on the upper end face of the blocking block; a fifth step of rotating the drill rod to enable the drill rod to be separated from the production casing, and lifting the drill rod upwards. A mining area ground coal-bed gas well casing device is further disclosed simultaneously to achieve the descending method. Descending and suspending of the production casing do not have influence on the drilling three-stage process, the production casing can be descended and suspended smoothly and accurately through the drill rod and can be suspended stably for a long time, and the influence of rock covering layer movement on the production casing in the coal mining process can be avoided. A descending and suspending process is simple simultaneously, construction is simple, and the method is safe and reliable and has wide practicality.