The disclosure provides an ink jet printing apparatus. The ink jet printing apparatus includes a support base configured to support the to-be-processed substrate; and a solvent adjusting mechanism, configured to supply a dummy region of the to-be-processed substrate on the support base with a first solvent that is same as a solvent in an ink and adjust a solvent atmosphere of the dummy region of the to-be-processed substrate on the support base, to make the solvent atmosphere of the dummy region of the to-be-processed substrate and that of a center region of the to-be-processed substrate reach a predetermined condition. The solvent adjusting mechanism is arranged on the support base.