Underground ball fishing device and ball fishing system

The invention relates to the technical field of underground salvage, in particular to an underground ball salvage device and a ball salvage system.The underground ball salvage device comprises an upper connector, a magnet sleeve, a magnet and a magnetism insulation sleeve, a liquid inlet cavity with an upward opening is formed in the upper end of the upper connector, and a liquid outlet which is through inside and outside and inclines downwards is formed in the position, corresponding to the lower portion of the liquid inlet cavity, of the upper connector; the lower end of the oil pipe joint is connected with the upper end of the check valve, the lower end of the check valve is connected with the upper end of the releasing tool, and the lower end of the releasing tool is connected with the upper end of the underground ball fishing device. The ball fishing device is reasonable and compact in structure and convenient to use, flushing fluid is pumped into an oil pipe, then the flushing fluid is sprayed into an a