A new formulation of inter-phase momentum transfer coefficient in solid-liquid two-phase analysis is presented. It is applicable over the range of void fraction (0.4 less than or equal to epsilon less than or equal to 1.0) useful in various engineering problems, agreeing with the resistance formulation for a single sphere in the range of large void fraction (epsilon greater than or equal to 0.8) and with Ergun＇s formulation in the range of small void fraction (epsilon similar to 0.4). Due to the new formulation, the problem of uncontinuity of the inter-phase momentum transfer coefficient at the point of epsilon = 0.8 is technically solved.