Objectives The nutritional components and feeding values of three commonly used roughages including green maize, sorghum and sunflower for sheep in Northern Shaanxi were studied to provide a reference for the further development and utilization of forage in the region. Methods The conventional method of analyzing feed was used to analyze the content of nutritional components including the crude ash (Ash), crude fiber (CF), crude fat (EE), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and the composition of amino acids in three types of roughages. The feeding values of three commonly used roughages were evaluated. Results Among the three commonly used roughages for sheep in Northern Shaanxi, sunflowers had higher content of crude protein (CP) and crude fat (EE), lower content of crude fiber (CF), neutral detergent fiber (NDF), and acidic detergent fiber (ADF). Sunflowers have good nutritional value, followed by sorghum and green maize. Sunflowers had the highest relative feeding value and organic matter digestibility (OMD), reaching 863.22% and 112.32%, with the roughage grading index (GI) of 147.59, belonging to the Grade I forage. Compared to green maize, sorghum had a higher content of total amino acids (TAA) and essential amino acids (EAA), reaching 0.9g/100g and 1.24g/100g, which can provide higher quality of protein for animals. Conclusions When feeding three commonly used roughages, priority can be given to feeding sunflowers and sorghum, followed by green maize.