The application of Windows 95/98/NT for PPP MO (Pariser-Parr-Pople molecular orbital) calculation was developed by using the Inprise C++ builder. The novel two-center electron repulsion integral (new-gamma), the concept of spectrochemical softness parameter krs for PPP calculation, was introduced in this application. The user can perform quickly the modeling of pi-conjugated compounds on a PC monitor and select many suitable parameters (for example, ionization potentials, resonance integrals etc.) for the PPP calculation. The SCF calculation was momentarily performed and oscillator strength and LCAO coefficients of HOMO, LUMO or others were displayed. The calculations Save satisfactory results for the prediction of the electronic absorption spectra of polycyclic aromatic hydrocarbons(PAHs), symmetric cyanins and so on.