A restricted‐access material–hybrid monolithic column was prepared based on single‐component organosiloxane and dynamic grafting of δ‐gluconolactone for on‐line solid phase extraction of tetracycline antibiotic residues from milk. The hybrid monolithic column was prepared in a stainless‐steel chromatographic column using methyltrimethoxysilane as the single precursor. δ‐Gluconolactone was covalently coupled to aminopropyl derivatized hybrid monolithic column, which formed hydrophilic structures on the surface of the pore of the restricted‐access material–hybrid monolithic column. The columns were characterized by scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, nitrogen adsorption, contact angle analysis, dynamic adsorption, and chromatographic performance evaluation. The restricted‐access material–hybrid monolithic column was applied to the on‐line extraction of tetracycline residues from milk. An enrichment factor of 15.8 and a good sample clean‐up effect were obtained under the optimized conditions. The recoveries of the three spiked milk samples were between 81.7 and 102.5% with relative standard deviations (n = 3) in the range of 2–5%. The limits of detection (S/N = 3) for target compounds were in the range of 3.80–9.03 μg/kg. The results show that the on‐line extraction using the restricted‐access material–hybrid monolithic column was powerful for food sample pretreatment with high selectivity and good clean‐up effect.