A method for measuring the gas volume flow rate and liquid volume flow rate in a gas-liquid mixed fluid, comprising the following steps: a. Forming a mixture of gas and liquid phases; b. Letting the gas-liquid mixed fluid to flow through a vertically arranged circular pipe with a superficial gas velocity of greater than 15 m/s, which is controlled by a valve, so as to form a stable-state gas-liquid two-phases annular flow; the gas-liquid two-phase annular flow referring to such a flow mode that the gas surrounds the axis of the circular pipe in a column form, while the liquid is distributed between the gas and the pipe wall in a ring form; c. Measuring the total volume flow rate Q, temperature T, pressure P and gas volume fraction GVF of the gas-liquid mixed fluid; d. Calculating the superficial gas velocity V s by the formula V s = Q × GVF/A, where A denotes the cross-sectional area of the circular pipe, and judging whether or not the calculated superficial gas velocity is greater than 15 m/s; e. Adjusting the valve to control the superficial gas velocity, so that the critical state for building the stable-state gas-liquid annular flow is reached; f. Calculating the gas-liquid slip factor S and the gas volume flow rate Q g and the liquid volume flow rate Qi based on the following equations: S = 2 − GVF / μ k × GVF − 1 Q g = Q × GVF × S / 1 − GVF + S * GVF Q l = Q × 1 − GVF / 1 − GVF + S * GVF wherein, Q denotes the total volume flow rate, the unit being m 3 /s; S denotes the ratio of the gas velocity (in m/s) to the liquid velocity (in m/s), dimensionless; GVF denotes the gas volume fraction, dimensionless; μ k denotes the ratio of the gas viscosity μ g (in any viscosity unit, e.g., Pa•s) to the liquid viscosity μ l (in any viscosity unit, e.g., Pa•s) at the measuring temperature T and pressure P of the gas-liquid mixed fluid, dimensionless. a. Forming a mixture of gas and liquid phases; b. Letting the gas-liquid mixed fluid to flow through a vertically arranged circular pipe with a superficial gas velocity of greater than 15 m/s, which is controlled by a valve, so as to form a stable-state gas-liquid two-phases annular flow; the gas-liquid two-phase annular flow referring to such a flow mode that the gas surrounds the axis of the circular pipe in a column form, while the liquid is distributed between the gas and the pipe wall in a ring form; c. Measuring the total volume flow rate Q, temperature T, pressure P and gas volume fraction GVF of the gas-liquid mixed fluid; d. Calculating the superficial gas velocity V s by the formula V s = Q × GVF/A, where A denotes the cross-sectional area of the circular pipe, and judging whether or not the calculated superficial gas velocity is greater than 15 m/s; e. Adjusting the valve to control the superficial gas velocity, so that the critical state for building the stable-state gas-liquid annular flow is reached; f. Calculating the gas-liquid slip factor S and the gas volume flow rate Q g and the liquid volume flow rate Qi based on the following equations: S = 2 − GVF / μ k × GVF − 1 Q g = Q × GVF × S / 1 − GVF + S * GVF Q l = Q × 1 − GVF / 1 − GVF + S * GVF wherein, Q denotes the total volume flow rate, the unit being m 3 /s; S denotes the ratio of the gas velocity (in m/s) to the liquid velocity (in m/s), dimensionless; GVF denotes the gas volume fraction, dimensionless; μ k denotes the ratio of the gas viscosity μ g (in any viscosity unit, e.g., Pa•s) to the liquid viscosity μ l (in any viscosity unit, e.g., Pa•s) at the measuring temperature T and pressure P of the gas-liquid mixed fluid, dimensionless.