<p>The positive charged chitosan, CS, and negative charged lignosulfonate, LGS, were mixed to form the CS/LGS mixed solutions with different concentrations and mixing ratios, and their rheological properties were quantitatively studied. Steady-shear viscosity measurements revealed that the mixing ratio is the predominant factor governing the rheological properties of these mixed solutions. Solutions with high CS content exhibited high viscosity and pronounced shear-thinning behavior, characteristic of the entangled polysaccharide networks. Conversely, the introduction of LGS above a critical ratio induced a significant viscosity drop and diminished shear-thinning, attributed to the electrostatic complexation and charge neutralization leading to the chain contraction. While the total concentrations have a measurable effect, its influence was secondary to the mixing ratio. These findings are corroborated by a proposed mechanism of electrostatic-driven assembly and collapse. This work provides crucial insights into the structure-property relationships of CS/LGS complexes, facilitating their tailored design for applications in the food processing, pharmaceutical formulations, personal care products, paints, etc.</p>