China has plenty of starch-rich agricultural leftovers, which can be degraded and further utilized for biogas production. Potato, which has more and more cultivated areas, was taken as a substrate. The pH, OD₅₄₀, biogas yield, hydrogen yield, biogas production rate, and hydrogen production rate were determined to evaluate the effect of substrate concentration on the photo-fermentation bio-hydrogen production process under an oscillation condition. Results showed that the photo-fermentation period was extended to 264 h under oscillation, which was two times longer than the static condition. It was found that 8 g per 100 mL fermentation broth was the most suitable substrate concentration under oscillation, the cumulative hydrogen yield was 510 mL VS⁻¹, and the hydrogen content was 38.36%.