The invention discloses a slope adjustable and underlying surface adjustable small-scale flowing fire simulation experiment device and method. The device comprises a flowing groove system, an oil supply system, an overflowing oil collection system and a data acquisition system, wherein the flowing groove system comprises a rectangular flowing groove, an underlying surface, a lifting table, a supporting table, a flowing stabilizing device and an optical leveling device, the oil supply system comprises a peristaltic pump, a hose and an oil supply barrel, the overflowing oil collection system comprises an oil outlet pipe and an oil collecting barrel, and the data acquisition system comprises a thermocouple array, a first camera, a second camera, a thermal infrared imager, an electronic balance, a data conversion module and a computer. According to the invention, parameters such as spreading distance, spreading rate, temperature, flame height and the like of flowing fire can be studied, sothat the influence mechanism of bottom surface gradient and underlying surface heat loss on fire spreading speed characteristics can be studied, and favorable basis and support are provided for emergency treatment of flowing fire accidents.