Camelidae can produce a unique antibody that lacks light chain called variable heavy chain domain, also known as nanobodies. This antibody contains only one variable region, with high affinity, high stability, strong tissue penetration, efficient expression. Besides, their toxicity and immunogenicity are both low to be used for both therapeutic and diagnostic applications, as well as research tools. In this review, we discuss how nanobody has been explored as therapeutics in oncology, and provide ideas for the further development of nanobody.