We investigate the nonlinear ion-acoustic solitary waves for a plasma model at Titan's ionosphere dayside. The plasma system composed of three positive ions, namely HCNH⁺, C₂H₅⁺, and CH₅⁺, isothermal electrons and streaming solar wind particles (i.e. protons and electrons). The dynamics of the ion-acoustic waves is described by Korteweg de-Vries (KdV) equation. The analysis has been done by using a reductive perturbation method. The solitary wave solution is obtained and the effects of solar wind parameters on the pulses profile are examined. Furthermore, the effects of the relevant physical parameters on the profiles of soliton waves are investigated. It is found that only positive pulses are existing and there is not any negative pulses. The soliton amplitude increases with the increase of the phase velocity λ and the relative density protons-to-HCNH⁺. Also, it was found that the pulses decrease with the increase of the relative density C₂H₅⁺-to-HCNH⁺ and temperature ratio protons-to-electrons.