CRISPR-based screening is a powerful high-throughput approach that systematically explores gene function by modulating gene expression at the genomic level. This method utilizes CRISPR-Cas systems—including CRISPR knockout (CRISPRko), CRISPR activation (CRISPRa), and CRISPR interference (CRISPRi)—to dissect gene roles across the genome. By introducing large-scale sgRNA libraries targeting coding genes, non-coding RNAs, and regulatory elements, researchers can map functional networks and identify context-specific vulnerabilities in various cell types and disease models. Compared to RNA interference (RNAi) or overexpression methods, CRISPR offers higher specificity, lower off-target effects, and supports both gain- and loss-of-function screening, making it the preferred tool for large-scale genetic interrogation and translational research.