Abstract: In order to increase anaerobic hydrogen production capacity and stability using complex materials, effects of pig manure (PM)/potato pulp (PP) mass ratio on specific hydrogen production rate (SHPR), VS degradation rate (VDR), and composition of dissolved fermentation products were investigated. Results showed that substrate composite affected the metabolism pathway of anaerobic hydrogen fermentation significantly. With sole PP as substrate, SHPR peaked at 31.55mL/g, at the same time VDR was 29.43%, and butyrate-type fermentation was formed. When PM/PP ratio ranged from 10:70 to 40:40, acetate-type fermentation replaced butyrate-type fermentation, and higher SHPR (22.48-24.18 mL/g) and VDR (28.31%-32.93%) levels were maintained. When further increased PM/PP ratio from 50:30 to 80:0, limitation of fermentation was presented due to high concentration of ammonia, and SHPR and VDR declined sharply. Modified Gompertz model could fit well the change of the accumulative hydrogen production with time, its kinetic parameters such as maximum hydrogen yield, maximum hydrogen production rate and lag time can be regarded as the important evaluation index for metabolic process of hydrogen production from mixed materials fermentation. This study provides a reference and foundation for the optimization of hydrogen production from anaerobic co-fermentation of mixing materials.