Anti-blocking device used for oil well pump

The utility model discloses an anti-blocking device used for an oil well pump and good in anti-blocking effect. The anti-blocking device comprises a lower connector connected with an oil pumping tube and an outer connecting pipe which is in threaded connection with the lower connector, a seal ring is arranged between the lower connector and the outer connecting pipe, the lower end, in the outer connecting pipe, of the lower connector is in threaded connection with a first inner connecting pipe, a valve base is arranged between the first inner connecting pipe and the lower connector, a second inner connecting pipe is welded to the rear end of the first inner connecting pipe, a sand prevention hole is formed in the second inner connecting pipe, a sand setting trough is arranged between the second inner connecting pipe and the outer connecting pipe, a conical cap is welded to the rear end of the second inner connecting pipe, channels are formed in the lower connector, the outer connecting pipe, the first inner connecting pipe and the second inner connecting pipe respectively, and a steel ball is arranged in the first inner connecting pipe. The anti-blocking device has the advantages that the sand setting trough is arranged, sand grains enter the sand prevention hole after being buffered, cannot cause blockage, can be effectively filtered out and are prevented from entering the oil well pump, and influences of the sand grains on the oil well pump can be effectively eliminated.