The overuse of antibiotics poses a serious threat to human health and ecosystems. Therefore, the development of high‐performance antibiotic removal materials has attracted increasing attention. However, the adsorption and removal of trace amounts of antibiotics in aqueous systems still face significant challenges. Taking tetracycline (TC) as a representative antibiotic and based on its structural characteristics, a series of TC adsorbents are prepared by grafting alkyl groups to the framework of MIL‐101(Cr). The adsorptive capacity of the modified materials for tetracycline markedly surpasses that of MIL‐101(Cr), with MIL‐101‐dod achieving the best adsorption performance. MIL‐101‐dod demonstrated an outstanding ability to adsorb tetracycline at low concentrations, where a 5.0 mg sample of MIL‐101‐dod can reduce the concentration of a 90 mL 5 ppm tetracycline solution to below 1 ppb, significantly superior to other sorbents. XPS and IR tests indicate that MIL‐101‐dod has multiple weak interactions with tetracycline molecules, including C─H…O and C─H…π. This work provides theoretical and experimental support for the development of adsorbents for low‐concentration antibiotics.