Submesoscale, with a typical scale of a few kilometers, has been recognized as an important process for energy cascades and heat transport. However, how submesoscale turbulence evolves under tropical cyclones has been rarely explored, particularly from in-situ observations. In this study, we use the cooperative observation of multiple gliders to analyze the characteristics of submesoscale instabilities within a mesoscale anticyclone during the passage of tropical cyclone “Haitang” in the South China Sea. During tropical cyclones, the probability of submesoscale instability was observed to be significantly intensified and different submesoscale instabilities show different spatial distributions within the mesoscale eddy. Such array observations of submesoscale dynamics under the influence of tropical cyclones can provide insights for improving submesoscale parameterization of climate-scale ocean models.