Abstract: The influence of austenization holding time on the morphology of pearlite in Fe-0.12%C alloy under high magnetic field (12 T) was investigated by optical microscopy. It was shown that the tendency that the long axis of the pearlite colonies is parallel and elongated along the magnetic field direction under the high magnetic field increases with the prolonging holding time for austenization. Under the conditions that the holding time for austenization and magnetic field both remain unchanged, the area fraction of the pearlite in the sample whose plate plane is parallel to the magnetic field direction is less than that in the sample whose plate plane is perpendicular to the magnetic field direction, and tendency that the long axis of the pearlite colonies is parallel to and elongated along the magnetic field direction is weaker.