The invention discloses a telescopic tube structure of a dust collector. The telescopic tube structure comprises an inner tube and an outer tube, the inner tube is inserted into the outer tube, and the inner tube is in sliding fit with the outer tube; an annular containing groove is formed in the end of the inner wall of the outer tube, and a sealing ring for sealing the outer tube and the inner tube is arranged in the annular containing groove; the sealing ring comprises a first half ring and a second half ring, and sealing insertion openings are formed the two ends of the first half ring respectively, sealing inserting strips are arranged at the two ends of the second half ring respectively, and the sealing inserting strips are inserted into the sealing inserting holes respectively. The structure has the advantages that the sealing ring used for sealing the inner tube and the outer tube cannot be damaged during assembling, and the quality of the assembled sealing ring is ensured.