The High Intensity Heavy-ion Accelerator Facility (HIAF) is a new major scientific infrastructure at the Institute of Modern Physics of Chinese Academy of Science (IMPCAS), which is expected to accelerate heavy ions to 12.0 GeV/u. To improve gradually heavy-ion beam energy, booster ring which is an important accelerator between i-linac and HFRS, is established for confine and deflect the heavy ion at HIAF project. As an important deflection component, a pulsed room temperature dipole magnet in booster ring is proposed. The aim of the present work is to characterize the behaviors of eddy current in the iron yoke and vacuum pipe and its effects on the quality of magnetic field during a fast-pulsed mode. For purpose of precise, 3-D numerical modeling for the pulsed room temperature dipole magnet, the iron yoke and vacuum pipe were performed to calculate their eddy current. Maxwell’s equations considering eddy current effects have been dynamically solved by means of finite element method. The influences of the ramping rates, materials and dimension of vacuum pipe on the eddy current profile and magnetic field distribution are also discussed in details. According to our analysis results, the paper provides some meaningful suggestions for the design of magnet and vacuum pipe at HIAF project.