Abstract: Due to the change of flow direction and the continuous radial inflow of wall fluid, the flow law of gas and water in horizontal wellbore is quite different from that in conventional vertical well. Based on summarizing the results of previous studies, the horizontal wellbore gas-liquid two-phase prediction model is selected. After verifying the reliability of the model, considering in the wall inflow and the change of gas-liquid flow pattern, and changing multiple factors such as gas flow rate, water flow rate, pipe diameter, dip angle, trajectory fluctuation, and inflow positions for gas and water, etc., this study conducts a comprehensive predictive analysis on flow patterns, pressure distribution law and influencing factors of the horizontal section, and which can provides a theoretical basis for the production management and optimization of horizontal gas wells. The results show that there are three types of flow patterns in the horizontal wellbore under normal production conditions, i.e., stratified flow, intermittent flow and annular mist flow. The diameter and inclination of the wellbore have the most obvious influence on the gas-water flow pattern of horizontal wellbore, while the pipe wall inflow has little effect on flow pattern in the local wellbore. The pressure loss of horizontal wellbore is positively correlated with the gas flow rate, water flow rate, upward inclination angle of trajectory and trajectory fluctuation, and negatively correlated with the pipe diameter and downward inclination angle. Within the predictive range, gas flow rate, upward inclination of trajectory and pipe diameter shows the most significant influence on the pressure loss of horizontal wellbore, which are the key influencing factors of the pressure drop of horizontal wellbore. As the inclination angle of trajectory increases, the pressure drop of horizontal wellbore shows a significant reversal with the change of gas flow rate. Under the condition of low gas flow rate, the pressure drop of horizontal wellbore will increase with the decrease of gas flow rate; under the condition of high gas flow rate, it will increase with the increase of gas flow rate.