Organic-inorganic perovskites have attracted increasing attention in recent years owing to their excellent optoelectronic properties and photovoltaic performance. In this work, the prototypical hybrid perovskite CH3NH3PbI3 is turned into a ferromagnetic material by doping Mn, which enables simultaneous control of both charge and spin of electrons. The room-temperature ferromagnetism originates from the double exchange interaction between Mn2+-I--Mn3+ ions. Furthermore, it is discovered that the magnetic field can effectively modulate the photovoltaic properties of Mn-doped perovskite films. The photocurrent of Mn-doped perovskite solar cells increases by 0.5% under a magnetic field of 1 T, whereas the photocurrent of undoped perovskite decreases by 3.3%. These findings underscore the potential of Mn-doped perovskites as novel solution-processed ferromagnetic material and promote their application in multifunctional photoelectric-magnetic devices.