Abstract: 0.2C-1.6Si-1.8Mn steel with initial martensite microstructures was subjected to austenitizing at different temperatures (840, 870, 910℃) and quenching-partitioning (Q&P) treatment. The effect of austenitizing temperature on the microstructure and tensile properties of the steel was studied. The results show that when the austenitizing temperature was in the two-phase region, the ferrite in the Q&P treated experimental steel was mainly banded, and the retained austenite was blocky and flaky. With the increase of austenitizing temperature, the content of ferrite and retained austenite decreased, and the content of martensite increased; accordingly, the yield strength and the tensile strength increased while the percentage elongation after fracture and the product of strength and elongation decreased. The higher percentage elongation after fracture of the Q&P treated experimental steel at austenitizing temperature of 840℃ was related to the higher content of the retained austenite with two forms of block and flake, which could effectively expand the transformation induced plasticity effect range.