Abstract: It is of great significance to investigate the competition relationships and compensation effects among crops in intercropping systems under different nitrate-to-ammonium nitrogen ratios, which is important for elucidating the mechanisms driving system stability and guiding rational fertilization practices. This study took wheat (Triticum aestivum) and faba beans (Vicia faba) intercropping system as subjects, different ratios of nitrate and ammonium nitrogen were used to measure crop yield and biomass under intercropping condition, namely nitrate nitrogen: ammonium nitrogen =4∶0(N1), nitrate nitrogen: ammonium nitrogen =3∶1(N2), nitrate nitrogen: ammonium nitrogen =2∶2(N3), nitrate nitrogen: ammonium nitrogen =1∶3(N4), nitrate nitrogen: ammonium nitrogen =0∶4(N5). By measuring the crop yields and biomass under monoculture and intercropping conditions, the root shoot ratio, aggressivity (AWF), relative intensity of impact (RII), net effect(NE), compensation effect (CE) and selection effect (SE) of intercropping were calculated to determine the effects of different nitrate and ammonium nitrogen ratios on interspecific competition and complementarity. The results show that the land equivalent ratio of intercropping crops was greater than 1 under different treatment conditions. Compared with other treatments, the partial land equivalent ratio of faba bean had significant differences and reached the maximum value under N2 treatment. There were no significant differences in the aboveground and underground biomass of wheat in monoculture and intercropping under conditions N1 to N5. Among all ammonium nitrate nitrogen ratio treatments, the AWF of wheat was all greater than 0, and AWF of wheat was the most obvious under N2 treatment. Compared with other treatments, the relative action strength (RII) of wheat under N2 was significantly increased by 1.4–6.3 times (P<0.05). The CE of the intercropping system is greater than 0, the selection effect SE is less than 0, and CE reaches the maximum value under N2 treatment. The interspecific competitiveness and relative interaction intensity of wheat were obviously stronger than faba bean in wheat and faba bean intercropping system. There was a positive correlation between interspecific competitiveness of wheat and CE, and there was a positive correlation between partial land equivalent ratio faba bean and CE in the intercropping system, respectively. In conclusion, different ratios of nitrate nitrogen to ammonium nitrogen affect the interspecific competitiveness and compensation relationship in the wheat-faba bean intercropping system, and thus influence the intercropping system yield. Treatment with a ratio of nitrate nitrogen to ammonium nitrogen of 3:1 (N2) has the most significant effect.