he resistance characteristics of air-water flow in spiral pipe were studied experimentally. The influences of mass flow rate and mass quality on pressure drop were analyzed. The empirical formula of the pressure drop was built up based on the method of dimensional analysis and the linear regression with experimental data tested at different conditions. The results showed that the pressure drop increased with the increase of gas-liquid mass flow rate and mass quality. The calculated value of the empirical formula was in good agreement with the experimental data and the formula was accurate enough to calculate the pressure drop of gas-liquid two-phase flow in spiral pipe.