The Spainsh mackerel ( Scomberomores commerson ) is one of the major commercial fish species for drift gillnet and trolling lines fisheries in waters of Taiwan. The total catch annual of Spainsh mackerel in Taiwan has been about 660 metric tones in 2017. The fork length, and body weight composition for samples collect from January to November 2017. The relationship between body weight (BW) and fork length (FL) was estimated as BW = 0.00006x 3.0868(r² = 0.9843, n=467). The mean length at first maturity (L 50 ) for females was 68 cm FL. The otolith to determine the age of this fork length is about 1 year. The waters were likely to be the nursery ground for Spainsh mackerel because the transparent eggs were collected in these waters from March to June. The water temperature was approximately 23 and 27℃ from March and July. Suggesting that Spainsh mackerel have a preference for temperature 23 to 25℃.