1. A method for scheduling cloud-computing resource, comprising: receiving a computing request; retrieving a computing resource table of each of a plurality of computing nodes, wherein the table buffered in a memory of a broker includes a computing pattern obtained from a load history record of each computing node, wherein every load history record is stored in every node's memory; calculating an availability of each computing node according to the computing request and the computing pattern; calculating a confidence of each computing node according to the computing request and the computing pattern; calculating an expectation value of each computing node based on the availability and the confidence; and selecting one or more computing nodes according to the computing request and the expectation value of each computing node; executing a computing task; and distributing the computing task to the selected one or more computing nodes.