The invention relates to an air jump bit for oil and gas fields to drill well, wherein an upper connector, an outer barrel, a lower connector and a drill head are connected in turn, the inner cavity of the outer barrel is provided with a boss and a groove, a supporting seat is sleeved on a central pipe and is positioned by the boss of the outer barrel, the central pipe is step cylinder shape, theinner cavity is provided with a step hole, the upper portion in the central pipe is provided with a plurality of slant through holes, and the inner cavity of the central pipe and the central pipe areled to be communicated with the ring-shaped space of the upper connector, the lower portion of the central pipe is provided with two straight holes, a flow quantity allocating piston is mounted on the lower end of the inner cavity of the central pipe, the central pipe, the upper connector and the cooperating portion of the supporting seat are all equipped with rubber pads, the piston is sleeved on the central pipe, the upper end and the lower end of the external surface of the piston are both provided with a plurality of axial grooves, and the grooves on the upper end and the lower end are crossed to process in a certain angle, the inner cavity of the piston is a step hole whose upper portion is big and lower portion is small, the inner cavity of the piston is provided with two radial ring grooves, and the corresponded positions are provided with radial holes, and the radial ring grooves and axial groove on the outer surface of the piston are communicated. The air jump bit is connected through a drill stem to be sent to the bottom of a well, the piston does reciprocal motion to impact a drill head under the function of air pressure, and drilling operation is achieved.