The field experiments was carried out at Bore Agricultural Research Center (BOARC) on Adola Sub-site, during 2015 and 2016 short rainy season with the objective of determining the most suitable time of introducing common bean and select the best common bean variety into maize and common bean intercrop. The experiment was laid out in randomize complete block design (RCBD) with three replications of factorial combination of three common bean varieties (Haramaya, Ibbado and Hawassa Dume) and four time of intercropping (Simultaneously with maize, 2 WAME, 4 WAME and 6 WAME) along with respective sole crops of common bean varieties and maize BH-661. Highly significant interaction effect of variety and time of intercropping were observed on days to flowering, maturity and plant height, whereby simultaneous intercropping of common bean variety provide longer days to flowering and maturity with taller and vigorous growth than delayed intercropping. A highly significant effect of time of intercropping was observed on number of pod plant-1 and seed pod-1, in which the highest mean number were recorded when common bean was simultaneously planted with maize compared to subsequent interseeding. Highly significant interaction effect of variety and time of intercropping were also observed on common bean varieties on hundred seed weight and grain yields, where drastic reduction of hundred seed weight and grain yields were observed due to delayed intercropping. In regards to maize components, only plant height and grain yield were significantly affected by main effect of time of intercropping, in which the highest mean plant height and grain yield were recorded in delayed time of intercropping common bean. On other hand total LER and GMV of Common bean and maize were significantly affected by main effect of time of intercropping. Simultaneous intercropping of common bean with maize proved LER and GMV of 1.36 and 20246 ETB ha -1 , respectively. Therefore, simultaneous intercropping of common bean with maize could be recommend for midland of Guji and similar agro-ecology, based on the observed productivity and economic benefit.