We fabricated solution-processed IGZO TFTs with various composition ratio of precursors according to the contents of In, Ga, and Zn. Threshold voltage of solution-processed IGZO TFTs was-0.43 V, 3.86 V, and 11.12 V when the composition ratio was varied by 7:1:2, 6:3:1, and 5:1:4, respectively. Saturation mobility of solution-processed IGZO TFTs was 1.4 cm 2/V·sec, 0.84 cm2/V·sec, and 0.3 cm 2/V·sec with the composition ratio of 7:1:2, 6:3:1, and 5:1:4 respectively. When In composition ratio increased, the threshold voltage decreased and saturation mobility increased because of the increase of electron concentration. When Ga composition ratio increased, the off-current was decreased because of the suppression of formation of oxygen vacancies. When Zn composition ratio increased, the hysteresis was decreased because of the reduction of interstitial states between channel and insulator.