In this paper, a strain HZ1 which was isolated in our former works was classified as Lactobacillus Casei (L. Casei) by 16S rDNA sequence analysis. The results of angiotensin-converting enzyme (ACE) inhibitory assay showed that this novel stain was able to produce ACE inhibitory components when it was used to fermented milk. Applying the methods of membrane filtration and anion-exchange chromatography with fast protein liquid chromatography (FPLC) system, nine fractions with remarkable ACE inhibitory activity were obtained, and two bioactive fractions, recorded as ACEI-2 and ACEI-5, exhibited the highest ACE inhibitory rate of 60.55% and 71.71%, respectively. Furthermore, seven fractions proteins/polypeptides, which exhibited ACE inhibitory rate higher than 50% were separated from ACEI-2 and ACEI-5 by using sephadex gel filtration chromatography. These works might provide a foundation for the following study of L. Casei HZ1 and its probiotics functions, and contribute to the development of functional foods or drugs that provide health benefits to patients suffering from hypertension.