Two schemes, hollow shaft and solid shaft were proposed for the cantilever high-speed rotor of a turbofan engine during the structural design stage. Based on the beam element finite element method, rotor dynamic analysis models with hollow shaft and solid shaft were established, and critical speed and vibration mode calculations were carried out. The calculation results show that hollow shaft structure is suitable for the rotor. Then, an analysis was conducted on the sensitivity of the unbalance response of a rotor with a hollow shaft to the unbalance amount at the characteristic position, providing a basis for the selection of balance surfaces in high-speed dynamic balance test. Finally, the dynamic characteristics test of the simulated rotor with hollow shaft within the full speed range and the high-speed dynamic balance test research at the working speed were completed. The rotor smoothly crossed the two orders bending critical speed and safely operated to the working speed, verifying the rationality of the rotor's hollow shaft structure and dynamic design. Compared with the experimental results, the calculation error of the established finite element model is not more than 4.08%, which well reflects the dynamic characteristics of the rotor. After high-speed dynamic balancing, the deflection of the rotor at the working speed is significantly reduced, not less than 33.33%. The research results provide reference and technical support for the structural, dynamic design, and experimental research of real low-pressure rotors, and has important engineering value.