Optical coherence tomography (OCT) enables non-destructive, non-invasive acquisition of high-resolution cross-sectional images of samples. Improving imaging speed has been one of the most critical research directions in OCT technology development. Line-field (LF) OCT technology offers a high-speed imaging solution by illuminating samples with line focusing and implementing parallel detection. Compared to traditional point-focusing OCT, LF-OCT can increase imaging speed by tens of times while maintaining phase stability and power safety advantages. Consequently, it has found widespread applications in biomedical and industrial inspection fields. This paper reviews the developmental history of LF-OCT, focusing on its general system architecture and significant technological innovations, along with major application cases across various domains. The advantages and limitations of LF-OCT are thoroughly analyzed, and effective improvement measures are proposed. Looking forward, LF-OCT is expected to expand its applications in functional imaging and industrial inspection. Particularly in dermatology, it shows promise to replace traditional point-focusing two-dimensional scanning OCT as the mainstream technology.