Preparation method of iron oxides with adjustable size, appearance and compositions

The invention discloses a preparation method of iron oxides with adjustable size, appearance and compositions. The preparation method comprises the steps of: adding ferric salt, sodium bicarbonate and organic amine to an organic solvent, and stirring to obtain a transparent solution; and carrying out heat treatment on the solution, carrying out centrifugal separation, and washing to obtain the iron oxides particles. The iron oxides particles comprise ferric oxide particles and ferroferric oxide particles, have the diameter of 10-600nm, and are solid, meso-porous or hollowly spherical in appearance. The preparation method is simple in preparation process; the yield of the iron oxides is high; the size distribution of the products is narrow, and the products have high saturated magnetic field intensity; the iron oxides with different sizes, appearances and compositions can be obtained by simply controlling reaction conditions; and the preparation method is significant for preparation and application of the iron oxide particles.