Fabrication of S-scheme heterojunctions with enhanced redox capability offers an effective approach to address environmental remediation. In this study, high-performance Bi 2 Sn 2 O 7 /β-Bi 2 O 3 S-scheme heterojunction photocatalysts were fabricated via the in situ growth of Bi 2 Sn 2 O 7 on β-Bi 2 O 3 microspheres. The optimized Bi 2 Sn 2 O 7 /β-Bi 2 O 3 (BSO/BO-0.4) degradation efficiency for tetracycline hydrochloride was 95.5%, which was 2.68-fold higher than that of β-Bi 2 O 3 . This improvement originated from higher photoelectron−hole pair separation efficiency, more exposed active sites, excellent redox capacity, and efficient generation of • O 2 − and • OH. Additionally, Bi 2 Sn 2 O 7 / β-Bi 2 O 3 exhibited good stability against photocatalytic degradation, and the degradation efficiency remained >89.7% after five cycles. The photocatalytic mechanism of Bi 2 Sn 2 O 7 /β-Bi 2 O 3 S-scheme heterojunctions was elucidated. In this study, we design and fabricate high-performance heterojunction photocatalysts for environmental remediation using S-scheme photocatalysts.