| We conducted two field experiments (2014 and 2015) to investigate the yield potential in sole and intercropping systems using various maize varieties (n=21) in maize-soybean relay strip intercropping system. Based on yield levels, the maize varieties were categorized into three groups, i.e., maize yield in sole and intercropping system higher than 7500 kg.hm-2 (SHIH), yield higher than 7500 kg.hm-2 in sole but lower than 7500 kg.hm-2 in intercropping system (SHIL), and yield lower than 7500kg.hm-2 in both sole and intercropping system (SLIL). We further investigated the plant morphological characteristics under different yield levels. Based on variation coefficient of morphological characteristics and correlation between morphological characteristics and yield, we observed that morphological characteristics such as leaf area, leaf angle above ear-position, height and ear height as were main indicants of high maize yield in intercropping system. However, we speculate that the leaf area per plant was the main parameter that was significantly affected the yield in SHIL. It is enticing to report that maize in SHIH group had high leaf area (6415cm2.plant-1-7158.cm2.plant-1). Two leaf angles above ear-position of plants in SHIH group were 20-31°and 22-28o. To sum-up, high yield of maize was correlated with the height and ear position, the yield was higher when the height of maize was around 259-280cm and ear position around 94.5-113.0cm.