Experiments and calculations were performed to study the dependence of the nonlinear dust oscillatory motion on electron temperature and gas pressure in direct current plasmas. The frequency spectra of the dust particle oscillations induced by an excitation wire were measured in different discharge conditions. At higher electron temperature in accordance with the higher cathode voltage, the nonlinear phenomena of the oscillation spectra became more prominent. The amplitude of the subharmonic resonance peak was large and the frequency shift of the primary resonance peak was observed to be more significant in the case of high electron temperature. The force profile near the particle trap position was calculated in order to understand the dependence of the oscillation spectra on the electron temperature and the electron density. The electron temperature dependence of the particle oscillation was well explained from the calculated force profile. In addition, it was experimentally shown that the amplitudes of both the subharmonic resonance and the primary resonance became large as the pressure was decreased, which was consistent with the calculation.