This paper develops a direct-computation Hopfield method for solving the economic dispatch (ED) problems of thermal generators. The method employs a linear input-output model for neurons. Formulations for solving the ED problems are explored. Through the application of these formulations, direct computation instead of iterations for solving the problems becomes possible. Not like the usual Hopfield methods which select the weighting factors of the energy function by trials, the proposed method determines the corresponding factor using formulation calculation. Hence, it is relatively easy to apply the proposed method. The effectiveness of the developed method is identified through its application to two example systems. Computational results manifest that the method has a lot of excellent performances, and it is superior to other methods in many respects.