This field experiment was conducted at the Koga irrigation site with the objectives of evaluating the effect of plant spacing and harvesting age on the morphological parameters, dry matter yield, and chemical composition performance of Brachiaria mutica grass intercropped with vetch (Vicia villosa) under irrigation conditions, North Mecha Amhara region, Ethiopia. The experiment was laid out using a randomised complete block design in a factorial arrangement consisting of two factors (plant spacings with three levels and harvesting ages with three levels) arranged into a total of nine treatments with three replications. There were three blocks, each containing nine plots, a total of twenty-seven plots. The plot size was 6 m 2 (3 m x 2 m). The harvesting ages were 60, 90, and 120 days and the between plant spacing of Brachiaria mutica set into 20, 30, and 40 cm and the between row spacing 10cm,15cm and 20cm .The experiment site was well prepared and established the Brachiaria mutica grass with root splitting.The Vetch (Vicia villosa) was seeded after the age of three weeks of Bracharia mutica grass sown or planted. annual forages fast growth than grass hence,to prevent shading or over domination. number of rows 5, 7 and 10 respecively and 6 plants per row in each spacing factor A set of data were collected from ten plants which were randomly selected within the middle raws. Plant height (PH), number of tillers per plant (NLPP), Leaf stem ratio (LSR) and leaf length per plant (LLP of Bracharia mutica grass were measured) and its dry matter yield was calculated. Similarly, PH, leaf area (LA), and LSR of vetch morphological parameters and its DMY data were recorded. The collected data were managed using MS excel 2010 and subjected to general linear model analysis of variance procedures of SAS package version 9.0 and Pearson correlation analysis, with a significance level of alpha 0.05. The current result indicated that plant spacing and harvesting age had a significant effect on morphological parameters, dry matter yield, and the chemical composition of Bracharia mutica intercropped with legume species of vetch. All plant morphological parameters (PH, NTPP, NLPP, LLP) and DMY except LSR were significantly higher p<0.001 at 120 days of harvesting age and wider plant spacing 40cm, except LLPP when Bracharia mutica grass intercropped with vetch. Plant spacing were not affected the DMY and LSR of vetch but the DMY was higher at the late harvesting age when vetch was grown with intercropping of Bracharia mutica. Besides these morphological parameters performances, the chemical composition of the miture was affected p<0.001 due to harvesting age. Intercropping of Bracharia mutica with vetch for optimum production of the forage with wider plant spacing (40cm) and 120-day harvesting age resulted in high performance of PH, NTPP, NLPP, and LL, while the ash, LSR and CP were reduced. Therefore, wider plant spacing (40 cm) and intermediate harvesting age (90 days) improved the quality of Bracharia mutica intercropped with legume vetch used as animal feed resources.