Finding efficient and reliable scour countermeasures has always been a research hotspot in marine engineering. Using solidified dredging soil as an underwater grouting material for scour protection has recently achieved remarkable results. This method has a wide material source, offers effective protection, and is ideal for managing dredging soil. Therefore, its application in scour protection projects has become increasingly widespread. In practice, the solidified soil is typically pumped into the scour pit in slurry form, gradually consolidating over time and eventually integrating with the surrounding seabed. However, the solidified slurry is prone to displacement and spreading by flow after entering water. As a result, its protective effectiveness is closely related to its rheological properties and anti-scour ability. To investigate the influence of various factors on these properties, this study conducted controlled experiments with varying additive contents and curing times. In the preparation of the slurry, SAC cement acted as the primary solidifier, while polyacrylamide and superplasticizer served as the thickener and water-reducer, respectively. The research thoroughly analyzed how the solidified slurry's initial fluidity, underwater anti-dispersion ability, and viscosity changed under these conditions. Additionally, the incipient velocity of the slurry was measured over time using an erosion function apparatus. Based on these findings, a relationship was established between the rheological properties and anti-scour characteristics of the solidified slurry, and an empirical formula was derived to predict the incipient velocity of the slurry.