Aiming at the competition rules of the 2D simulation survival challenge of underwater robots in the International Underwater Robot Competition, an obstacle avoidance strategy that is beneficial to “dodge fish” is proposed. The area simplification of the grid method is used to divide the site area to realize the divide and rule, and combine the actual situation to realize the dynamic conversion strategy between the areas. Practical results show that the use of this strategy can make “dodge fish” more effective in avoidance, and make the simulated robotic fish move more flexibly between sites.