In order to explore the engineering properties and parameter distribution characteristics of lakebed sedimentary soft soils of Taihu, a large amount of experimental data of lakebed soft soils along the Taihu tunnel was collected. The value range, variability, probability distribution model, and spatial distribution pattern of physical and mechanical parameters were systematically analyzed. Then, the correlations between soil property indexes of various soil layers were explored. The results show that the physical and mechanical parameters of lakebed soft soils have high variation coefficients and no obvious functional variation pattern in spatial distribution. The plastic limit and liquid limit satisfy a normal distribution, the density and dry density approximately follow a normal distribution, while other parameters do not conform to a normal distribution. The most significant physical indexes related to the intensity parameter of soft soil are natural water content, natural void ratio and dry density, respectively, which have exponential or power functions in relation to those mechanical indexes. Compared to compression modulus, the coefficient of compression has a better correlation with natural water content, natural void ratio, and dry density. The correlation coefficients between intensity parameters and deformation parameters of clay are the largest, followed by mucky soils and silty clay, and silt has the smallest correlation coefficients.