Abstract: Based on the current related researches, a complete style of interval linear programming was defined. All the coefficients of its objective function and constraints can be interval numbers, and its constraint conditions may be equations or inequations. An order relation between interval numbers reflecting the satisfactory level of decision makers was proposed, and based on this, inequality constraints of interval linear programming were transformed into constraints with exact coefficients. The equality constraints of interval linear programming were discussed and converted into inequality constraints with exact coefficients. In addition, its objective function concluding interval numbers was analyzed and changed into an exact objective function. As a result, an interval linear programming problem was transformed into an exact linear programming problem and solved. Finally, an example was given.