This invention relates to the process of a kind of ultra-low contraction polyester fiber industry filament, which introduces the spinning and stretch one-stage process, including: solid phase increases sticks, melting spinning, high temperature stretches, heat setting, coiling formation. This invention adopts the innovative 5 pairs of hot rollers stretch heat setting technique, in comparison with the tradition 4 pairs, which adopts the 2-step heat stretch and 2-step heat setting. The new level heat setting processing method can reduce the textile fiber stretch speed effectively, lengthen the textile fiber heat setting time, and enables the textile fiber possessing evenly stable orientation structure, which guarantees product physics performance, optimizes the spinning condition. This ultra-low contraction polyester fiber industry filament preparation method provided with polyester fiber industry having high density, big module, small elongate, good heat-resisting performance, resisting impingement, and bearing the fagged performance.