In the processes of deep hole drilling and boring, tool deflection and chatter are prevalent problems that significantly affect the quality and efficiency of deep hole part machining. This paper designs a Helical-Type Vibration-Damping and Deflection Correction Device for BTA (boring and trepanning association) deep hole drilling based on the principles of fluid dynamic pressure lubrication and squeeze film damping. By leveraging the flow field characteristics of cutting oil during machining, the device achieves vibration-damping, deflection correction, and enhanced support for the tool system throughout the drilling operation. Through theoretical analysis, this research examines the oil film pressure distribution and stability of the Designed Vibration-Damping and Deviation Correction Device. It also explores the influence patterns of factors such as cutting parameters, device structure, minimum film thickness, film thickness ratio, and length-to-diameter ratio on its vibration-damping, deviation correction, and stability performance. Taking a $\varphi 29.35$ deep hole as the research object, an experimental platform was designed and constructed to measure and verify the device’s vibration-damping and deviation correction effects under different operating conditions. Deep hole drilling tests were carried out on 10 conventional gun steel specimens ($\varphi 29.35$ × 3000 $\mathrm{m}\mathrm{m}$). The results indicate that, when the minimum oil film gap of the Vibration-Damping and Deflection Correction Device is 0.08$\mathrm{m}\mathrm{m}$, the axis deviation range is 0.27~0.45$\mathrm{m}\mathrm{m}$, with a surface roughness of 0.589 to 0.677$\mathsf{\mu }\mathrm{m}$. Compared to similar conditions without the device, these represent reductions of 55~73% and 47.07~53.95%, respectively. It allows for a reduction of over 10% in blank material allowance and an increase of 5–15% in tool feed rates.