The Ruddlesden-Popper (RP)-type strontium iridate (SrIrO 3 and Sr 2 IrO 4 ) epitaxial thin films are selectively grown from a single Sr 2 IrO 4 target using pulsed laser deposition. The stabilization of the SrIrO 3 and Sr 2 IrO 4 phase is sensitive to oxygen partial pressure (P O2 ). Low laser fluence tends to expand the growth window of pure Sr 2 IrO 4 films. The lower P O2 (≤2.6 Pa) is preferred for preparing Sr 2 IrO 4 films, while the SrIrO 3 phase forms at higher P O2 (≥6.5 Pa). The growth diagram for SrIrO 3 and Sr 2 IrO 4 films has been summarized, providing a powerful guideline for fabricating the epitaxial films of single RP-type strontium iridate phase.