In this paper, we designed the platinum octahedral complex as an anti-cancer drug by applying it to the Gaussian 09W program. The physical properties were calculated using the DFT / B3LYP density function theory for basis sets (LANL2DZ), we also calculated the ultraviolet-visible spectrum (UV), the infrared spectrum (IR), the stability energy, the HOMO and LUMO orbits, the Global properties, and the difference between them and studied the reduction of the octahedral complex to a flat square and its hydrolysis inside the human body, then compared its association with the nitrogenous bases that make up the DNA through nitrogen atom number (N7) and then its association With DNA strand and the results showed that the designed compound achieved high chemical rigidity when linked to methyl. DNA and this indicates its biological effectiveness towards cancer inhibition and compare this result with the well-known treatment against cancer, which is cisplatin, theoretically using the same method and the same basis.