Abstract: The rapid development of high-pressure common-rail system technology and the continuous increase in injection pressure have created an urgent demand for high-pressure fuel pipe materials with higher strength grades. To address this need, 0.2% Cr (mass fraction) was added to the steel used for 16MnNiV small-diameter seamless steel tubes, and cold-drawn small-diameter seamless steel pipes with an outer diameter of 8 mm and an inner diameter of 3.6 mm were successfully fabricated. The resulting tubes exhibit a tensile strength of 972 MPa, a yield strength of 950 MPa, and an elongation after fracture of 15%. Scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy were employed to characterize the specimens after cold drawing and subsequent heat treatment. The results show that the addition of 0.2% Cr refines the pearlite interlamellar spacing, shifting its maximum proportion interval from 110-130 nm to 70-90 nm, while also enhancing the stability of pearlite during cold drawing. Combined with Thermo-Calc 2023a thermodynamic calculations and experimental results, the addition of Cr reduces the absolute value of the driving force for precipitation of cementite and VC, thereby suppressing their precipitation and consequently decreasing the desolvation of C. Furthermore, Cr doping into VC to form (V,Cr)C increases the interfacial energy from 0.594 to 0.646 J/m², which facilitates the refinement of VC particles. Quantitative calculations of the strengthening mechanisms indicate that the dominant contributions from the addition of 0.2% Cr are, in descending order, solid-solution strengthening (204.7 MPa), dislocation strengthening (191.2 MPa), and precipitation strengthening (103.3 MPa).