[Objective]In order to study the effects of germination on the mass fractions of phenolic acids in black wheat, a method was established for simultaneous determination of 11 phenolic acids (gallic acid, protocatechuic acid, 4-hydroxybenzoic acid, chlorogenic acid, vanillic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid, sinapic acid, and salicylic acid) in germinated black wheat based on high performance liquid chromatography (HPLC).[Method]The mobile phase composed of methanol (containing acetic acid at a volume fraction of 1%) and water (containing acetic acid at a volume fraction of 1%) was used for gradient elution at a flow rate of 1 mL/min, a detection wavelength of 280 nm, and a column temperature of 25 ℃, to determine the mass fractions of 11 phenolic acids in black wheat on the 1st, 3rd, 5th and 7th days of germination.[Result]The results of methodology validation showed that 11 phenolic acids had a good linear relationship between mass concentration and peak area within the mass concentration range from 20 to 200 μg/mL, R²≥0.999 4 (n=6). The established method showed the limit of detection (LOD) ≥1.22 μg/mL and the limit of quantification (LOQ) ≥2.54 μg/mL for the phenolic acids. The relative standard deviations (RSD) of peak area of precision, repeatability, and stability were all less than 2.00%, and the average spiked recovery rates were between 98.02% and 101.12%, indicating that the established method was fast, accurate, and reliable. The extraction conditions were optimized as extraction with the solid-liquid ratio of 1 g∶30 mL and methanol at a volume fraction of 80% by vortex for 6 min, under which the total mass fraction of 11 phenolic acids in germinated black wheat was the highest. The results showed that during germination, the mass fraction of gallic acid in black wheat reached the peak on the 3rd day of germination. The total mass fraction of 11 phenolic acids was the highest on the 5th day of germination, which was 2.13 times of that in the non-germinated control group. This indicated that germination changed the mass fractions of phenolic acids in black wheat.[Conclusion]This study evaluated the effects of extraction conditions on 11 phenolic acids and determined the mass fractions of the 11 phenolic acids in germinated black wheat. The findings lay a foundation for the study of functional components in germinated black wheat and provide a reference for the quality control and evaluation of its products.