Abstract: The pneumatic vertical shock test system, due to its open-loop control, complex structure, and stringent test tolerance requirements, makes shock response spectrum (SRS) tuning particularly challenging. To address this, three key input parameters–gas source pressure, felt thickness, and impactor mass–were experimentally investigated using a controlled-variable approach on different transfer fixtures to determine their effects on the SRS. The results reveal significant coupling effects between these parameters. Notably, despite structural variations, each parameter consistently effects the SRS. These findings, corroborated by structural dynamic analysis, provide practical guidelines for SRS calibration.