One of the tasks of agricultural ecologist is to increase agricultural yield. How to improve agricultural practice is the biggest challenge in drought and barren environments on the Loess Plateau. Many studies have attempted to increase yield through the integration of plant population density, water and fertilizer use efficiency in this region. Intercropping, which is the simultaneous growing of two (or more) crop species in the same field, is a good solution to resolve this problem. Especially under low input conditions, the high yield attributes to resource complementarity in the intercropped system in which the component crops use the resources efficiently by dynamically balancing the different absorbing time, space-occupying or phenology. Maize (Zea mays L.) and soybean (Glycine max L.) are important crops in China selected as the inter-planted crops. A field experiment was conducted to investigate the yield and economic benefit in the intercrops of maize (Zhengdan 958 and Yuyu 22) with soybean (Zhonghuang 24 and Zhonghuang 13) in two planting patterns (2:2 and 2:4) respectively on the Loess Plateau, and the sole crops set as controls. Based on the interrelation between varied components and planting patterns as well as their relation to crop yield, competition indices, economic indices and water use efficiency under intercropped, we look forward to understanding potential regulation and mechanisms of maize/soybean intercropped system and serving for the agricultural production. The aboveground biomass, grain yield and water use efficiency were surveyed in each planting pattern. Several indices of competition and economic were calculated and used to evaluate the intercropped systems and analyze the competitive relationships between intercropped components. The results showed that the land equivalent ratio (LER) and relative crowding coefficient (K) were greater in maize-soybean intercropping than that in sole crop, indicating an advantage of intercropping. Yield of maize in maize-soybean intercropping was higher than that in single crop. The actual yield loss (AYL), aggressivity (A) and competitive ratio (CR) indicated that maize was the dominant species in maize/soybean intercropped system. Zhengdan 958 and Zhonghuang 24 showed more competitiveness on the water than the other two varieties in intercropping cultivation. The highest values of monetary advantage index (MAI) and intercropping advantage (IA) were recorded by the intercropping pattern of Zhengdan 958 and Zhonghuang 24 (with 2:4). The highest water use efficiency of maize was in intercropping pattern of 2:4, followed by intercropping pattern of 2:2, and sole crop was the lowest. As mentioned above, maize and soybean intercropped system had an obvious advantage in enhancing yield. The increases in biomass, yield and water use efficiency were caused by different varieties interaction and plant patterns significantly. Zhengdan 958 intercropped with soybean (Zhonghuang 24 and Zhonghuang 13) had advantage, indicating that Zhenggdan 958 is able to improve intercropping advantage. Zhengdan 958 and Zhonghuang 24 intercropped in patterns of 2:4 obtained the highest yield and water use efficiency among all treatments. Therefore, we suggest that Zhengdan 958 and Zhonghuang 24 intercropped in patterns of 2:4 had the highest economic benefit than the other patterns and thus may be adopted and popularized by farmers.