In live streaming commerce, the streamer group is the core factor that drives product's sales performance. This study aims to understand how the combinations of streamers volume, product's line breadth, and brand type influence brands'sales performances in live streaming commerce. The study collected panel data on Douyin live streaming platform in an 18-week period from August to December 2020 of 17 luxury brands and 27 non-luxury brands that are representatives of the cosmetics industry, which includes 261 streamers, 1,658 products and 3,119 live broadcasts. We used a two-way fixed effects model with STATA software, and found that streamer volume has a significant inverted U-shaped impact on brands' live sales, and the breadth of product's line has a significantly direct positive impact on brands' live sales. Besides, product's line breadth and brand type moderate the above inverted U-shaped effect.