In this letter, we presented that the charge quantity is the critical factor for forming process. Forming is a pivotal process in resistance random access memory to activate the resistance switching behavior. However, overforming would lead to device damage. In general, the overshoot current has been considered as a degradation reason during the forming process. In this letter, the quantity of charge through the switching layer has been proven as the key element in the formation of the conduction path. Ultrafast pulse forming can form a discontinuous conduction path to reduce the operation power.