单链抗体（single chain fragment variable, scFv）是通过基因工程改造过的重组抗体，保留了抗体的靶向性，同时因为其体积较小而获得了完整抗体不具有的特性，例如渗透性好、易扩散、免疫原性弱、体内存留时间短以及容易表达等。这些特性使得scFv可以作为一种十分理想的靶向性分子应用于疾病的诊断和治疗。scFv可以与荧光蛋白融合发挥疾病诊断的作用；也可以与化学毒素相连形成免疫毒素用于癌症的治疗；ScFv连接到T细胞上，则构建成嵌合抗原受体T细胞，是十分具有前景的癌症治疗技术。此文综述了scFv的相关制备技术，以及一些比较有希望的临床及临床前应用。

Single chain fragment variable (scFv) is a recombinant antibody that has been genetically engineered. scFv retains the targeting properties of antibodies, while acquires properties that intact antibody does not have, such as good permeability, easy diffusion, weak immunogenicity, short in vivo retention time and easy expression, due to its small size. These properties make scFv ideal for diagnostic and therapeutic applications as a target molecule. It can be fused with fluorescent proteins for disease diagnosis and linked to chemical toxins to form immunotoxins for cancer treatment. Chimeric antigen receptor-T technology is a promising technology for cancer treatment by linking scFv to T cells as a targeting molecule. This article reviews the techniques related to the preparation of scFv and some promising clinical and preclinical applications of scFv.