The invention discloses a heat-flow meter for measuring heat flux of aluminium oxide inside a solid rocket engine dynamically in real-time. The heat-flow meter comprises a heat-flow meter body including a cylindrical heat-sink copper piece and a constantan piece that are arranged coaxially. A thermal-insulation ceramic plate that is used for cooling high-temperature heat flux at the surface of the constantan piece is arranged at the top of the constantan piece coaxially; and the outer sides of the thermal-insulation ceramic plate, the constantan piece, and the heat-sink copper piece are coated with a beryllium-oxide ceramic housing and the thermal-insulation ceramic plate is fixed at the top of the constantan piece by the beryllium-oxide ceramic housing. The beryllium-oxide ceramic housing is used for guiding one part of heat flux to the matrix of the heat-sink copper piece. A heat-sink copper hole is formed along the axis direction inside the heat-sink copper piece; and a thermocouple for measuring the top temperature of the heat-sink copper piece is installed approaching the constantan piece inside the heat-sink copper hole. Therefore, a problem that condensed-phase particle washing or density measurement of disposition heat flux inside a solid rocket engine can not be realized on the high-temperature, high-pressure, and high-heat-flux conditions can be solved.