In order to address the challenges of solid waste resource utilization and low-carbon urban development, this study prepared alkali-activated cementitious materials (AACM) at ambient temperature using ground granulated blast-furnace slag (GGBS) and sewage sludge ash (SSA) as partial replacements for fly ash (FA), with sodium silicate and NaOH solutions as alkaline activators. The orthogonal experimental method was employed to investigate the effects of water-to-binder ratio (A), sodium silicate modulus (B), and liquid-to-solid ratio (C) on the performance of geopolymers. Results demonstrated that the optimal mix proportion included 10% SSA (mass fraction), water-to-binder ratio of 0.5, sodium silicate modulus of 1.1, and liquid-to-solid ratio of 0.4. This formulation extended the initial and final setting times of AACM paste by 23.1% and 62.3% , respectively, reduced mortar fluidity by 17.24% , while achieving 28-day compressive and flexural strengths of 54.4MPa and 7.75MPa. The order of influence significance was determined asA ＞B＞ C for workability parameters, and A＞C＞ B for both compressive and flexural strength development.