The present invention relates to a polyester fiber applicable to an airbag fabric, and more particularly to a polyester fiber, a preparation method for the polyester fiber, and an airbag fabric prepared from the polyester fiber, where the polyester fiber has an elongation of 0.8 to 2.0 % under a tensile strength of 1.0 g/d at the room temperature, and an additional elongation of 1.5 to 5 % under a tensile strength of 8.8 g/d to the maximum.
The polyester fiber of the present invention which secures low initial Young's modulus and good mechanical properties can be used in an airbag fabric not only to provide excellences in air sealing effect as well as packing property and dimensional stability but also to minimize collision impacts on occupants, thereby protecting the occupants with safety.