Abstract: We evaluated the effects of trawl wing length (Lw) on the performance of trawl gear with large-size mesh. Trawl model tests were carried out in a towing tank at East China Sea Fisheries Research Institute. We measured the effect of Lw/L on the resistance, height of net mouth, and hydrodynamic performance of the trawl by testing six wings of differing lengths attached to trawls of equal longitudinal length (L). Trawl resistance increased with increasing Lw/L, but was relatively constant when Lw/L exceeded 36.45%. As Lw/L increased, trawl resistance increased at higher speeds. The height of the net mouth increased as Lw/L increased, reaching a maximum when Lw/L was 36.45%–38.69%, then declining. The effect of Lw/L on the height of the trawl mouth was not influenced by trawling velocity. There was little change in the height at lower speeds but a significant change at high speeds. The hydrodynamic performance of the trawl was highest when Lw/L was>36.45%, and decreased as Lw/L increased further. We conclude that an Lw/L of 36.45% is optimal when designing wing length. However, in practice it may be necessary to lengthen the wing of a trawl based on actual operating conditions.