Abstract: Cementitious materials are indispensable in engineering construction, and their quality guarantees the safety of construction projects. Therefore, it is crucial to conduct quality inspections on cementitious materials. Nondestructive testing technology, especially ultrasonic nondestructive testing technology, has gained attention due to its high efficiency and strong penetrating ability. The full-waveform inversion algorithm is a highly accurate imaging method used in seismic exploration, offering advantages such as multi-parameter modeling and high-precision imaging. In this study, we conducted tests on the fissure morphology of cement specimens and evaluated their grouting quality with full-waveform inversion algorithm. The experimental results demonstrate that the full waveform inversion imaging method effectively reflects the morphology of cement fissures. Additionally, employing a serial inversion strategy can prevent falling into local minima during inversion and improve accuracy. Furthermore, utilizing the double-difference method effectively reduces background field interference while highlighting slurry diffusion locations. These research findings provide valuable insights for applying ultrasound in detecting cement fissures and evaluating grouting effectiveness.