The optimation of sustainably of local feed resource is a strategy to use rice straw as a beef cattle feed. This research was carried out in two steps: 1) potency of rice straw in North Penajam Paser, Kutai Kartanegara, Berau Regency. The research method used analitic survey with observation technique. The locations determined based on purposive sampling to the wide of rice straw harvested area. Populations of beef cattle as a based of determined carrying capacity to rice straw availability and, 2) rice straw potency can be known through labolatorium experiment with proximat analysis. The results showed that the average of rice straw productions in last five years +16.584; +13.239; +13.767; +24.347; and +21.974 tons. Average populations rached 2.21 AU; 2.34 AU; 2.34 AU; 2.43 AU, and 2.51 AU. Average needs of beef cattle feed 17.327 tons/year; 18.580 tons/year; 18.521 tons/year; 19.948 tons/year and 19.963 tons/year. Average of each carrying capacity 1.97 AU/year; 1.57 AU/year; 1.63 AU/year; 2.82 AU/year; and 2.51 AU/year. The results proved that rice straw quantity and quality potentially to fulfill needs of beef cattle feed in North Penajam Paser, Kutai Kartanegara, and Berau Regency.