Based on the definition of the best submain position locations in which the same minimum pressure exists in uphill and downhill laterals, a method was developed for designing micro-irrigation paired laterals with emitters at homologous discharge rate, allowable maximum and minimum pressure along laterals were conditions needed to satisfy. When the designed emitter discharge, emitter space and one or two parameters (length, diameter or pressure head) of a paired lateral were provided, the unknown parameters and the best submain position could be designed at any field slope conditions. The results show that the final solutions can be obtained quickly and reasonably.