The high-energy H++H impact excitation process in Debye plasma is investigated using impact parameter Born approximation method. In the cases of several different values of Debye length D, the inter-nuclear distance R of matrix elements, the weighted probability at a collision energy of 160 keV/u, and impact excitation cross sections in an energy range of 100–1000 keV/u for direct 1s → 2p transition in H for both the unscreened and screened Coulomb interactions are calculated. It is demonstrated that the magnitude of impact excitation cross section gradually reduces as screening parameter increases. According to the excitation cross section formula and the calculated results, a detailed analysis of the reason for the reduction caused by excitation cross section is given in this paper. The effects of screened Coulomb interaction on the potential of between incident particles and excited electronic and on the hydrogenatomic structure (wave function and energy level) have very important influence on the excitation cross section.