The pH value is one of the most important factors affecting iron reduction in paddy soils. The objective of this study was to determine how changes in initial pH affected iron reduction in paddy soils from Jilin (JL) and Jiangxi (JX) provinces. Anaerobic incubations were conducted using (1) soil slurries and (2) mixed microbial cultures that had been isolated from each soil type. The pH value of the alkaline JL samples was reduced with Al₂(SO₄)₃. The pH value of the acidic JX samples was increased using Na₂CO₃. The pH values of the soil slurries were strongly acidic (pH < 5.0), acidic (pH 5.0-6.5), neutral (pH 6.5-7.5), alkaline (pH 7.5-8.5), and strongly alkaline (pH > 8.5). The mixed microbial cultures were incubated in medium with pH ranging between 4.84-10.51. The Fe(Ⅱ) concentration and pH value of the samples were measured at regular intervals. A logistic model was used to analyze the characteristics of Fe(Ⅲ) reduction. The results showed that iron reduction potential and the maximum rate of iron reduction decreased as the initial pH value decreased. The time to reach the maximum rate of iron reduction increased as the initial pH value of the JL soil slurry declined. The maximum rate of iron reduction in the JL slurry decreased by nearly 50% as the pH value decreased, declining from (0.05±0.00) mg·g^-1·d^-1 at pH 10.51 to (0.02±0.00) mg·g^-1·d^-1 at pH 7.00. All amorphous iron oxides were reduced in the JX paddy soils, although the maximum rate of iron reduction increased and the time to reach the maximum rate of iron reduction decreased as the initial pH increased. The maximum rate of iron reduction in the JX soil was highest ((0.46±0.04) mg·g^-1·d^-1) and the time to reach the maximum rate of iron reduction was shortest ((3.65±0.21) d) at pH 8.19. There was a highly significant positive correlation between the maximum rate of iron reduction and the initial pH value of both soils (JL r=0.897, P=0.000; JX r=0.903, P=0.000). Mixed microbial cultures from both the JL and JX soil reduced all ferric iron, regardless of the initial pH value. It finally indicated that the iron reducing ability of microbial communities from both paddy soils were similar during the early stages of incubation but became different during the later stages. This observation provided support for the idea that facultative iron-reducing bacteria contribute to iron reduction in paddy soils. In the mixed cultures, the initial pH value increased. This was especially evident in the JX soil where the time to reach the maximum rate of iron reduction increased nearly six-fold, from (7.49±0.03) d at pH 4.84 to (45.2±0.3) d at pH 10.51. The maximum rate of iron reduction by the JL microbial community was negatively correlated with the initial pH value (r=-0.838, P=0.000). The maximum rate of iron reduction was highest at pH 6.00. The maximum rate of iron reduction by the JX microbial communities was highest at pH 4.84. There was a significantly negative correlation between the maximum rate of iron reduction and the initial pH value of the JX microbial community (r=-0.913, P=0.000). In conclusion, the effect of initial pH and soil type on iron reduction was significant in paddy soils. The initial pH has a certain influence on microbial communities and soil components.