Abstract: Aim To theoretically study on therelation between electronic structures and its medical properties.Methods The theoretical study of the electronic structures andits interaction micromechanismof Pt compounds was carried out by density functional method.Results and Conclusion The computational results indicated that the exchange dy namic equilibrium ofinteraction be tween first g eneration or second generation medical molecule and DNA could berepresented by the interaction streng th of Pt-Cl bond.The order is DDPC<Pt(en)₂CL₂<PtC₄N₃H₁₃Cl<DDPB<DDPA.The toxic-side Effect and antitumour do sage wereanalyzed successfully.Our theoretical results werein go od agreement with the experimental results. The equilibrium geometry was optimized and the stability was discussed.The electronic affinity, ionization potential and Mulliken populations werealsocalculatedin this article.

Key words: Pt complexes as antitumour drug, electronic structures, theoretical chemistry