Abstract: The delta is usually located in the transition zone between large surface water bodies such as rivers, lakes and oceans, supporting about 8% of the world's population. However, the delta system is considered to be a highly sensitive and vulnerable zone of many ecosystems due to multiple factors such as low terrain, reduced sands from the upstream river and rising sea levels, thus has attracted lots of attention from policymakers, scientists and inhabitants. In recent years, surface hydrological connectivity has become a hot issue in hydrology and hydrodynamics research of river delta. This study presents a review of surface hydrological connectivity in the river delta area. Based on bibliography analysis, the concept and composition of surface hydrological connectivity in the river delta were introduced, and its relationship between delta morphology was then discussed. The results show that delta surface hydrological connectivity can be classified into structural connectivity, functional connectivity and process connectivity. Structural connectivity based on graph theory only characterizes the role of river networks in hydrological connectivity in the river delta, while functional connectivity and process connectivity reflects the spatial distribution of hydrodynamic elements and their coupling with meteorological and other environmental factors, which needs effective field observations and survey datasets. In addition, delta morphology and hydrological connectivity are related, and some morphological indicators can be used to describe surface hydrological connectivity in the river delta, such as nearest-edge distance, synthetic sediment fluxes and nourishment area. Due to the high spatial and temporal heterogeneity and complex topography of the delta, the multi-disciplinary research strategies such as field observation, mathematical statistics and numerical simulation should be adopted in the future to improve understanding of hydrological connectivity in the river delta. This paper provides references for the study of environmental effects of deltas under the influence of climate change and human activities, and also provides a scientific basis from hydrology perspective for major environmental issues such as the adapting of delta wetland ecosystems to the rapidly changing environment.