To develop specialized starter cultures suitable for high-acid and high-ethanol environments, this study aimed to systematically screen lactic acid bacteria (LAB) with excellent stress tolerance and fermentation performance from sauce-flavor Baijiu distillers' grains. A tiered screening strategy was employed: initial isolation of acid-producing strains on bromocresol purple plates, followed by identification based on morphology, Gram staining, and 16S rRNA gene sequencing. The identified strains were then subjected to secondary screening for ethanol tolerance (5%–15%). The dominant strains were systematically evaluated for their acid tolerance (pH 2.0–6.0), temperature tolerance (20–60 ℃), in vitro safety (hemolytic activity and antibiotic susceptibility), and growth characteristics. Their practical application potential was finally assessed via solid-state fermentation experiments. Approximately 100 acid-producing isolates were obtained initially. After purification and identification, 24 strains were confirmed as LAB, belonging to five species: Pediococcus acidilactici, Pediococcus pentosaceus, Lactobacillus paracasei, Lentilactobacillus buchneri, and Lactobacillus acidophilus. At the critical ethanol concentration of 8%, the survival rates of strains such as P. acidilactici F8, L. paracasei F16, and L. buchneri F18 remained around 10%. Most strains maintained survival rates exceeding 60% after 2 h of exposure to pH 3.0–6.0. Temperature tolerance tests indicated optimal growth at 30–37 ℃. Safety assessments revealed that the four dominant strains exhibited no hemolytic activity and were susceptible to most tested antibiotics. In solid-state fermentation, L. paracasei F16 achieved a viable count of up to 7.33 × 10? CFU/g (wet weight) in a 70% distillers' grain medium after 48 h, which was significantly higher than that of other strains. This study successfully obtained three LAB strains possessing excellent acid and ethanol tolerance, temperature adaptability, safety, and efficient fermentation capacity. These findings provide core microbial resources and a technical basis for the high-value utilization of sauce-flavor Baijiu distillers' grains, thereby laying a foundation for developing fermentation starters for harsh environments.