| With the acceleration of urbanization, the accumulation of storage sludge in the Hunhe River Basin has increased year by year, creating a potential and long-term threat to the environment. In order to realize the resource-saving and harmless treatment of storage sludge, the composition of storage sludge and the evolvement rule were analyzed and researched. The basic physicochemical properties (water content, pH, volatile organic compounds (VS), and total alkalinity), nutrient index (TC, TN, C/N, TK, and TP), microbial composition, and heavy metal contents and fraction were analyzed. The results showed the VS and various nutrient element contents decreased with the prolongation of storage time, and changes in water content were not obvious, which was independent of the storage time and only relevant to natural conditions. The pH was maintained at around 7, and the bacteria predominated in microorganisms, accounting for about 90%. The content of anaerobic microorganisms increased. The contents and fractions of Cu, Zn, Cr, Ni, Pb, Cd, As, and Hg did not change significantly, but the content of Cu was higher than the Chinese standard for agricultural utilization (GB 4284-1984). Therefore, there is a larger risk of storage sludge for agricultural use. Therefore, the analysis of the composition and evolution of storage sludge in the Hunhe River Basin is of great significance for further resource treatment of sludge.