In the past two decades, extensive and in-depth research has been conducted on Time Series InSAR technology with the advancement of high-performance SAR satellites and the accumulation of big SAR data. The introduction of distributed scatterers in Distributed Scatterers InSAR (DS-InSAR) has significantly expanded the application scenarios of InSAR geodetic measurement by increasing the number of measurement points. This study traces the history of DS-InSAR, presents the definition and characteristics of distributed scatterers, and focuses on exploring the relationships and distinctions among proposed algorithms in two crucial steps: statistically homogeneous pixel selection and phase optimization. Additionally, the latest research progress in this field is tracked and the possible development direction in the future is discussed. Through simulation experiments and two real InSAR case studies, the proposed algorithms are compared and verified, and the advantages of DS-InSAR in deformation measurement practice are demonstrated. This work not only offers insights into current trends and focal points for theoretical research on DS-InSAR but also provides practical cases and guidance for applied research.