Purpose <p>Existing studies often equivalent shock absorbers to linear springs when conducting dynamic analysis of perforating string in ultra-deep wells, ignoring the impact of actual structure on dynamic response. Therefore, this study aims to establish a more accurate dynamic model, reveal the actual damping mechanism of shock absorbers, and provide a basis for optimizing shock absorption design and preventing tubing failure.</p> Methods <p>Based on D'Alembert's principle, this paper establishes a dynamic response evolution model for full-size shock absorbers at the instant of perforating by considering the perforating string structure and the shock absorber size. In addition, this paper conducts a dynamic response study on tubing strings with and without shock absorbers, and carries out a comparative analysis of vibration characteristics.</p> Results <p>It reveals that the top and bottom of the tubing are vulnerable positions, and the shock-absorbing effectiveness of the dampers is reduced due to the delay effect caused by the shear pins. According to the new vibration reduction method that solely employs a spring-damping system proposed in this paper, the maximum equivalent stress at the top and bottom ends of the tubing can be reduced by 73.94%, and the maximum axial stress can be reduced by 74.04%.</p> Conclusion <p>Increasing the spring wire cross-section size, the number of spring coils, and the spring pitch can effectively enhance damping capability, which provides support for optimizing shock absorber design and preventing tubing string failures.</p>