Based on the analysis of depositional environment, sediment sources, underwater topographic change, and shallow sediment activity, this paper discusses the stability of Majia shoal. The results reveal that:(1) Majia shoal is an underwater sand ridge consisting of coarse sandy deposition of over 10m thick, and the sediment source is limited; (2) Majia shoal has not an obvious change in shape and location during the past many years, and the underwater topography has been keeping stable; (3) The shoal sediment is difficult to be washed off even under strong wind and wave, so Majia shoal can keep stable for years.