In this paper the data on the humid period and its parameters are used to assess the agricultural production of the Loess plateau.The mean humid period (G) and its coefficient of variation (C) and aridity index (A) are related to the cropping system and the risk level of agricultural production.The mean wet (W) and dry (D) spells within the humid period and their standard variations (α,β) are related to the possible drought and water-logging disasters.The above-mentioned parameters can be also used to assess the agricultural climatic environment and the agricultural production potential of the Loess Plateau.