Due to its high carbon and low impurities contents, as well as good reactivity, biochar can partly or totally replace coal or coke as a promising reducing agent in metallurgy. This study offers a new method to produce qualified metallized pellets for steelmaking after microwave-assisted self-reduction of iron ore-biochar composite pellets. The key point was to prepare green composite pellets with good quality indexes which also allowed sufficient self-reduction under microwave irradiation. For this purpose, core-shell iron ore-biochar composite pellets were prepared with inhomogeneous biochar distribution. It was found that high grade iron concentrates A and B could be used together for improving pelletizing. Controlling the distributions and proportions of iron concentrate B (different additions in the core and shell) and biochar (all located in the core of the pellets) would contribute to high-quality iron ore-biochar green composite pellets with the drop number of 3.6 times/0.5 m, compressive strength of 11.1 N/p, and decrepitation temperature of 410 degrees C under the pelletizing conditions of total proportion of iron concentrate B of 30%, pelletizing time of 16 min, rotation speed of 25 r/min, bentonite dosage of 23%, C/Fe mass ratio of 0225, pellet moisture content of 13.0%, and proportions of iron concentrates A and B in the shell of 10% and 0%, respectively. The subsequent microwave reduction tests showed that the core-shell metallized pellets with the total iron content and metallization degree of 89.15% and 95.52%, respectively, could be obtained after microwave reduction at 1050 degrees C for 30 min under N-2 atmosphere. They had better reduction indexes than those produced from the pellets with homogeneous structure, serving as a good burden for steelmaking directly. (C) 2018 Elsevier B.V. All rights reserved.