The assembly of medium-scale collagen in native tissues promotes excellent performance and multiple functions. The preparation of collagen fibers and fiber bundles from collagen-rich tissues through acid swelling^[1,2] and the utilization of combined chemical and physical treatments have been documented^[3]. Homogenization and grinding were employed to enhance collagen nanofibrillation, albeit with high energy consumption. In this study, two simple and controllable liquid exfoliation methods were used to extract collagen fine structures directly from bovine Achilles tendons. One method utilized a sodium hydroxide (NaOH)/urea water system to extract collagen fibers with diameters ranging from 26~230 nm through freeze-thaw cycles and ultrasound. The other method involved the use of a urea/GuHCl deep eutectic solvent to extract interstitial collagen fibers with diameters ranging from 102~159 nm directly from bovine Achilles tendons. In situ observation under polarized optical microscopy (POM) and molecular dynamics simulations revealed the effects of these two methods on tendon collagen. FTIR results confirmed that these original fibers retained the typical structural characteristics of type I collagen. Subsequently, these extracted collagen fibers were used as building blocks to prepare independent collagen membranes, which exhibited good transparency, strong mechanical properties, excellent barrier performance, and cell compatibility.