A considerable number of experimental work on the influence of flux ratio on variable mass flow in perforated completed horizontal wells has been published by many scholars，but the effects of perforation phasing，perforation diameter and perforation density on frictional，mixing and total pressure drop have not been studied systematically. In this paper，an experiment system is developed to investigate the influence of the perforation phasing，diameter and density. Three values of screw perforating phasing (45°，90°，180°)，three kinds of perforation density (8 meter-1，16 meter-1，24 meter-1) and three sizes of perforation diameter (10 mm，20 mm，30 mm) are considered in the experiment of this paper. In the experiment，the Re (Reynolds number) of axial flow in pipe ranges from 1 000 to 20 000，the flux ratio (the ratio of the radial volume inflow at unit wellbore length to the axial volume flow in production pipe) ranges from 0.01% to 10%. The results indicate that：the frictional and total pressure drop increases while mixture pressure drop reduces with the increase of the perforation density and perforation diameter；the “mixing”，frictional and total pressure drop all increases with the increase of the perforation phasing；the proportion of frictional pressure drop to total pressure drop reduces while the proportion of “mixing” and acceleration pressure drop increases with the flux ratio；the “mixing” and acceleration pressure drop increases with the flux ratio，but there exists a critical value of flux ratio. When the actual flux ratio less than the critical value，the “mixing” pressure drop is negative，the acceleration pressure drop is almost 0 that induces the total pressure drop less than the frictional term. When the actual flux ratio is bigger than the critical value，the “mixing” pressure drop increases to positive，and the acceleration pressure drop increases with the flux ratio obviously.