This standard specifies the high performance liquid chromatography method for the determination of vitamin D3 in feed. The first method of this standard is applicable to the determination of vitamin D3 in compound feed, concentrated feed, compound premixed feed and vitamin premixed feed, with a limit of quantitation of 12.5 μg/kg (500 IU/kg). The second method of this standard is applicable to the determination of vitamin D3 in vitamin premixed feed, and the limit of quantification is 125 mg/kg (5×10 IU/kg).