Fermented butter starter cultures have long been dependent on foreign sources. To develop an excellent lactic acid bacterial starter culture suitable for fermented butter, lactic acid bacteria were isolated from Guangdong buffalo raw milk, Hebei goat raw milk, Inner Mongolia cow raw milk, Inner Mongolian milk curd, and Tibetan kefir grains. Core strains were obtained through preliminary and secondary screening using butter-selective medium, followed by 16S rRNA gene identification. Stepwise screening was conducted based on sensory evaluation, fermentation performance ( growth curve,acid production curve), biosafety (hemolytic activity, antibiotic susceptibility), and probiotic properties (β-galactosidase activity, acid tolerance, bile salt tolerance, antibacterial activity). A total of 11 core lactic acid bacterial strains were obtained, all of which met the safety requirements for food-grade microorganisms, with nine strains achieving sensory scores above 80. Lactococcus garvieae DZ demonstrated excellent fermentation performance, with fast growth and rapid acid production initiation. Its β-galactosidase activity was 0.271 U·mL-1, with a survival rate of 94.75% at pH value of 3.0 and 40.43% in 0.3% (m/V) bile salt. It showed weak antibacterial activity against six foodborne pathogens. This strain demonstrated comprehensive advantages in butter matrix adaptability, sensory quality, fermentation performance, gastrointestinal tolerance, and probiotic properties, making it a preferred candidate for the development of fermented butter and providing theoretical and experimental basis for the development of specialized starter cultures.