This study is an emergy evaluation of Mai Po mangrove marshes. The important emergy indices of the system are as follows, the total output emergy of the marshes is 26.391017 sej: year; its macroeconomic value is 25.87105 per year (in 1988 Hong Kong); its emergy density is 6.941011 sej:m2 per year; and its investment ratio (IR), environmental loading ratio (ELR), yield ratio (YR) are 0.48, 1.03, and 3.10, respectively. The emergy of education function in Mai Po was tentative calculated as 125.651017 sej: year, its macroeconomic value is 123.19105 $ per year (in 1988 Hong Kong), in which the knowledge distribution is outstanding, about 99.261017 sej: year, the macroeconomic value is 97.31105 $: year (in 1988 Hong Kong), occupied 92% of all investments of whole education system. These data show that used emergy of per area in Mai Po is high and the management and education function of the natural reserve is good, but environmental loading is high.