This study presents an experimental investigation into the fuselage vibration characteristics of a three-bladed helicopter scale model induced by its rigid main rotor operating at variable speeds. Vibration accelerations along the fuselage x 、 y and z directions were measured using dedicated vibration analyzer instrumentation. Tests employed three geometrically identical scale-model rigid blades. Measurements were conducted across a collective pitch range of θ = 5~12° and rotor speeds from Ω = 500 to 1200r/min. The vibration analyzer software was utilized to analyze the harmonic content, specifically the 1st through 8th harmonic accelerations, under various operational states. Key findings reveal that: Low-order harmonic accelerations exhibit a significant increasing trend with rising rotor speed. Rotor speed is quantitatively identified as the predominant factor influencing fuselage vibration levels, followed by collective pitch angle. These experimental results provide valuable insights into the vibration generation mechanisms of variable-speed rotors, offering foundational data to inform future vibration suppression strategies and the design of variable-speed helicopters.