A device for preventing abrupt blockage in blooie line of gas drilling includes a sand-storing tank body, which is connected to a rotating blowout preventer through a guiding tube, and a guiding three-way joint is set between the guiding tube and the sand-storing tank body and connected to a blooie line by a vertical guiding tube; the sand-storing tank body is connected to the blooie line by means of a gas discharge tube; a flap plate assembly is arranged at the position fronting straight onto the guiding three-way joint inside the sand-storing tank body, and configured to control the rock particles in the guiding tube to enter the sand-storing tank body, preventing blockage in the blooie line. The device can effectively solve the technical problem that the process of gas drilling for oil-and-gas exploration and development is prone to abruptly block the blooie line.