In order to improve the bottle blowing speed for twostep linear electric highspeed PET bottle blower,based on the characteristics and technological requirements of bottle blowing machine,the structure of variable pitch screw was designed.According to the efficiency analysis result of variable pitch screw,the acceleration force caused by variable pitch of manipulator group was calculated.The lubrication between the slider and the surface of screw thread was analyzed,and according to DawsonHigginson formula,the minimum oil film thickness under different lubricating oils was calculated.By comparing the lubrication effect of the lubricating oils with different dynamic viscosity and viscositypressure coefficient at different stirring speed,an extreme pressure compound lithiumbased grease was selected as the lubricant of screw thread and slider.Experiments show that the blowing speed of the bottle blower with the variable pitch screw can reach 1.8 bottles per second,which is close to the international advanced level.