Helium can improve storage density and reduce power consumption of hard disk drives． In air-helium gas mixtures，the percentage of helium will affect the air bearing force of a slider and the air shearing force of a disk surface，which leads to lubricant transfer at the head /disk interface． In this research，the finite element method was used to solve the modified Ｒeynolds equation． The air bearing force of the slider and the air shearing force of the disk surface in air-helium gas mixture were calculated． The effect of flying gesture，disk velocity，and environmental temperature on the mechanical properties of the slider and the disk were investigated． The results show that，in air-helium gas mixtures，the air bearing force of the slider and the air shearing force of the disk surface decrease with an increase in flying height． The air bearing force and the shearing force increase with an increase in disk velocity and temperature． With an increase in pitch angle and roll angle，the flying height decreases，which leads to an increase in the air bearing force． However，the effect of the pitch angle and the roll angle on the air shearing force of the disk surface in air-helium gas mixtures is negligible．