Monodispersed Fe 3 O 4 /polypyrrole (PPy) hollow particles were synthesized via controllable in-situ deposition and polymerization techniques using poly(styrene-co-acrylic) (PSA) latex as template. Field-dependent magnetization plot illustrates that the capsules are superparamagnetic at 300K. FTIR spectrum confirms that the myoglobin (Mb) molecule adsorbed on the surface of Fe 3 O 4 /PPy hollow particle essentially retains its native structure. Furthermore, direct electrochemistry of Mb can be realized on Fe 3 O 4 /PPy capsules modified pyrolytic graphite disk electrode, which indicates that the magnetic conductive polymer capsules can promote the electron transfer of protein.