The pressure effect on the small amplitude solitary waves in a complex superthermal plasma composed of electrons, ions and dust is discussed. The Korteweg-de-Vries (KdV) equation and its model solution are derived using standard reduction perturbation techniques. Pressure is shown to significantly affects the existing mode in a superthermal environment. The imperative role is played here by the spectral index κ and the dust charge that strongly affect the properties of the nonlinear structures. The results obtained are compared with those acquired by the homotopy perturbation method (HPM). We see a strong correlation in the small time limit with our analytical calculations and those obtained by the HPM technique.