In cloud computing, cloud providers can offer cloud consumers two provisioning plans for computing resources, namely reservation and on-demand plans. Reservation plan is cheaper than that provisioned by on-demand plan, since cloud consumer has to pay to provider in advance. By using reservation plan, the consumer can reduce the total resource provisioning cost. Even though, the best advance reservation of resources is difficult to be achieved due to uncertainty of consumer’s future demand and providers’ resource prices. Due to this problem, an Optimal Cloud Resource Provisioning (OCRP) algorithm is proposed by formulating a stochastic programming model.