The experimental system of metal fuel/water ramjet was introduced.The unchoked ramjet of metal fuel containing magnesium can burn steadily after once injecting water.In the experiment

the mass flux of water was stable and the pressure of chamber changed similarly with the secondary chamber.The effect of once water/fuel ratio and fuel burn rate for the ramjet was studied through experiments.The results show the combustion and injection efficiency for ramjet firstly increase

and then decrease with the increase of water/fuel ratio in a define range of ratio;also

the combustion efficiency and the operation performance are improved observably by increasing the burn rate of fuel metal whose variation must under the need of the long time operation for the ramjet.