We study the dynamics of test particles around a static and spherically symmetric magnetized Ernst black hole considering its magnetic field in the environment surrounding the black hole. We show how its magnetic filed can influence on the dynamics of particles and epicyclic motions around the black hole. Based on the analysis we find that the radius of the innermost stable circular orbit (ISCO) for both neutral and charged test particles and epicyclic frequencies are strongly affected as a consequence of the impact of magnetic field. We also show that the ISCO radius of charged particles gets decreased rapidly. It turns out that the gravitational and the Lorentz forces of the magnetic field are combined, thus strongly shrinking the values of the ISCO of charged test particles. Finally, we obtain the generic form for the epicyclic frequencies and selected three microquasars with known astrophysical quasiperiodic oscilations (QPOs) data to constrain the magnetic field. We show that the magnetic field is of the order of magnitude B ∼ 10 −7 Gauss, taking into account the motion of neutral particles in circular orbit about the black hole.