Abstract: Based on theoretical analyses and flume experiments, an expression of destabilizing flow velocity for filled sandbags under the action of water flow is given. According to the expression, a kind of low price geotextile sandbag with comparalively high friction coefficient is developed. And the aging experiments of bags indicate that the sandbags almost lose their entire strength after they are exposed in air for six months, but their strength hardly falls when placed in store or under water.