The correlation feature of quantum light field is an important subject of quantum optics research. With the in-depth study on the subject, the researchers have also made a series of great progress in the correlation of classical light. Especially, by combining the orbital angular momentum of light, which has drawn much attention in the recent 20 years, a series of counterparts of high-dimensional quantum light have been observed. In this review, the related research of classical optical correlation in orbital angular momentum beams is summarized, the local inseparability in orbital angular momentum and its application are introduced, and the classical optical correlation in spatially separable orbital angular momentum is discussed as well. In particular, as a potential quantum process research platform, the random walk research based on the orbital angular momentum of classical light is also introduced.