• The first-principal calculations suggest a metallic ground state for S r 2 R u O 4 . • The introduction of fluorine in S r 2 R u O 4 opens the band gap. • The external uniaxial strain drastically alters the optical properties of S r 2 R u O x - 4 F x quaternary alloy. The effects of fluorine substitution and uniaxial strain on structural electronic and optical properties of superconductor S r 2 R u O 4 are investigated using the first-principal calculations. Band structure simulation suggests a metallic ground state for S r 2 R u O 4 , whereas the introduction of fluorine opens the band gap of aforementioned material. Results revealed that S r 2 R u O 4 - x F x (x = 2) quaternary alloy is an indirect-semiconductor with an energy gap of 1.519 eV. The electronic properties of S r 2 R u O 2 F 2 can be tuned by applying an external compressive and tensile strain (CTS) and also the absorption ability is improved under pressure. Other optical properties such as optical band gap, Urbach energy and optical conductivity in both x and z directions are studied. The obtained results might be useful for visible-light photoelectrical device applications.