The invention discloses environment-friendly iron oxide red for permanent magnetic ferrite and a preparation method. The method comprises the steps of A, screening, B, grinding and silicon removal, C,pre-oxidation, D, re-oxidation, E, annealing, F, powder preparation and G, testing, wherein chemical component analysis is conducted on the iron powder in the step of testing. According to the method, firstly, iron scales are dissolved, then various inorganic and organic high-molecular polymers are added, on the basis of a polyferric sulfate and cationic guar gum composite silicon removal agent,high-molecular polymer sodium alginate is added, the high-molecular polymer sodium alginate can be used as a carrier to adsorb colloidal silicon particles in a solution, meanwhile, the sodium alginatecan enable the polyferric sulfate and the cationic guar gum to stably exist in a weakly acidic system, and the coagulating sedimentation effect, the electric neutralization capability and the bridgeadsorption effect of a silicon removal agent are fully exerted, so that the purpose of deep silicon removal is achieved.