The invention provides a cache replacement method for a cache node. The method comprises the following steps of: only storing cache objects, of which the size is smaller than a predetermined maximal size, in the node; calculating values of the cache objects according to parameters of the cache objects stored in the node; maintaining a priority list of all the cache objects according to a magnitude relation of the values of all the cache objects in the node; and under the condition that total size of all the stored cache objects is equal to the maximal storage capacity of cache space of the node, taking out the cache objects with lowest priority from the list to perform replacement. Parameter values of size of the cache objects for calculating the values of the cache objects are logarithm values of actual size values of the cache objects. By the technical scheme of the invention, resource utilization rate and cache hit ratio of the cache space of the node can be improved effectively, byte hit ratio of the node can be improved, and global hit ratio of a cache system can be improved.