The current study presented was established an expert system technology of alfalfa (ESTA) program contains two copies (language English and Arabic) in terms of computer programs designed to mimic the reasoning of human experts was established. These programs, are able to take into account the relative importance of different criteria to the user. These program are useful in varieties aginst biotic and abiotic stress. And expert system is able to search a computer database to select the varieties that appeared the best reflect this particular bias. The result of this search is a list of cultivars ranked as to how well they meet the user's request. It is designed to incorporate detailed information about alfalfa (Medicago sativa L.) production regarding site, soil, machinery, management levels and yield information to simulate the annual costs and returns over the alfalfa (Medicago sativa L.) stand life. ESTA requires information from several domains of expertise such as agronomy, entomology, agricultural engineering and agricultural economy.ESTA is a form of artificial intelligence, may soon become an important management tool for agribusiness dealers, county agents, agricultural consultants and farmers. ESTA can make the specialized knowledge of an expert available to farmers when making critical management decisions. ESTA also can informs the user as to how the recommendation or conclusion was reached on the screen or on the print – out. ESTA modules procedures used by a forage expert in determining agro economic recommendations for successful establishment and production of alfalfa. With ESTA information is readily available to alfalfa producers for making management decisions relative to liming, fertilization, irrigation, drainage, weed control, longevity of stand, variety recommendations, method and rate of seeding. This study describes a microcomputer program called ESTA which is an expert system for alfalfa cultivar selection. ESTA is an expert system used as an educational tool for extension people and the alfalfa growers.