The invention discloses a semi-aromatic polyamide resin. The semi-aromatic polyamide resin is composed of derivatives of the following repeating units: (i) diacid units, (Iii) diamine units and (iii)one or more optional amino carboxylic acids and/or lactams, wherein terephthalic acid units account for 50 to 100 mol% of the component (i) based on the total molar weight of the component (i); aliphatic diamines with 11 to 20 carbon atoms account for 50 to 100 mol% of the component (ii) based on the total molar weight of the component (ii); the component (iii) accounts for 0 to 25 mol% of the total molar weight of the component (i) and the component (ii); and the content of bio-based carbon in the semi-aromatic polyamide resin is 56 to 100 mol%. According to the invention, the semi-aromatic polyamide resin prepared by using long-carbon-chain diamines and controlling the content of bio-based carbon is reduced in environmental influence and has Ganz whiteness value of 50 or more and a goodcolor level; and the molding composition composed of the semi-aromatic polyamide resin has obvious advantages in the aspect of color performance.