A new analytical model has been developed for determining the wetting phase relative permeabilities in a multiple gasliquid drainage process. The multistep drainage process consists of a series of drainage processes with a tiered pressure-difference profile. With this model, the wetting phase relative permeabilities can be readily obtained through regression of the wetting phase recovery history. The assumptions used in deriving the analytical model are examined by numerical simulations. The agreement between the analytical and the numerical results indicates that these assumptions are reasonable and valid. Numerical simulations and laboratory results demonstrate that this model is effective for direct estimation of the wetting phase relative permeabilities in the multistep drainage process.