Abstract: With its advantages of high precision and high horizontal resolution, the submarine gravity survey has improved the Marine exploration technology system and provided support for basic geological research, resource exploration, major engineering construction and geoid elaboration. Through the sea floor gravity survey in Bohai Sea, about 15 000 km² gravity data have been obtained, and the influencing factors and evaluation methods of the accuracy of sea floor gravity survey have been studied. Compared with the land area, the accuracy of seabed gravity survey has many interfering factors, which are mainly affected by water depth, seabed sediment, sea condition, plane and elevation survey accuracy, near area terrain correction and so on. Taking bouguer gravity anomaly as evaluation index, this paper studies and analyzes the influence of various factors on the accuracy of seabed gravity measurement. The results show that: ① In ultra-shallow water, the environmental disturbance has a great influence on the accuracy of seabed gravity measurement; ② Hard bottom area, high gravity measurement accuracy; ③ The wind has little influence on the accuracy of seabed gravity measurement, and the waves and currents caused by it will have limited influence on the observation accuracy; ④ The influence of plane positioning accuracy on seabed gravity measurement accuracy is relatively small; ⑤ Elevation is the most important factor affecting the accuracy of seabed gravity measurement; ⑥ In the gentle region of submarine topography, the effect of near-area terrain correction on gravity accuracy can be negligible. At the same time, the relative gravity value method, Bouguer gravity anomaly method and gravity anomaly interpolation method are evaluated. Through research and analysis, the evaluation method with Bouguer gravity anomaly as the index is more reasonable and conforms to the characteristics of seabed gravity measurement.