Abstract: Wind and wave dissipation of tidal flat vegetation plays an important role in the embankment protection. The flow resistance mathematical models for mangrove porous media were built based on the momentum conservation equation and exponent equation using porous media source of speed. The effects of different factors on the flow resistance of mangrove were analyzed by using computational fluid dynamics software, Fluent. The results showed that the dissipation effect was involved in the porosity, the width of shelterbelt, and the depth of wave. Of which, the effect of water depth on wave dissipation was most obvious. With the increase in the porosity, the wave velocity increased sharply at first, and then increased slightly as the porosity was more than 0.4. With increase in the forest belt width, the wave velocity decreased at different degree. The fitting results of Logistic equation based on 4 parameters showed that wave velocity presented a decrease tendency of anti-S-Shape with increase of the forest belt width. Based on above results, a new approach was put forward for evaluation of the effect of mangroves on wave dissipation.