The mean rate of methane production from soils of Avicennia marina mangrove forest at Dongzhai Harbor in Hainan Province and at Western Harbor in Xiamen were 3.59 and 11.59 ng/gd, respectively. It was higher than that of a coastal barren shoal (1.62ng/gd) and lower than that of a mangrove forest slash (48.96ng/gd). The mangrove vegetation may enhance methane production from costal wetland due to decay of its roots.There were similar seasonal patterns of methane production rates (warmer season's>colder season's) in the two mangrove forest.By multi-factor linear regression analysis, we concluded that soil water content,organic matter, Ca²⁺,Mg²⁺ and SO₄^2- had great effects on methane production rates of the mangrove forest in Hainan, while soil water content,total N and Cl^-/SO₄^2- ratio had great effects on mangrove forest in Xiamen.