The invention discloses an on-site energy-storage liquid foam drilling fluid generating device and a method. The on-site energy-storage liquid foam drilling fluid generating device comprises an energystorage liquid foam generator and a static mixer; the energy storage liquid foam generator comprises a pedestal; the front surface of the pedestal is provided with an energy-storage foam pressure relief opening union; the bottom of the energy-storage foam pressure relief opening union is provided with an energy-storage foam outlet union. According to the on-site energy-storage liquid foam drilling fluid generating device, a high power foam generator is adopted, so that it is beneficial for increasing of the pressure resistance of energy-storage liquid foam, gas with certain pressure is introduced into the high power foam generator through the union; and at the same time, a variable-frequency speed-adjustable high pressure temperature proportioning pump is driven to take foaming liquid from a dilution liquid foaming tank into the high power foam generator for mixing with gas, initial energy-storage foam fluid is generated with stirring conditions, and the static mixed is adopted, so that it is beneficial for obtaining of stable and uniform energy-storage liquid foam drilling fluid.