1. A method for sharing online storage services among multiple users, the method comprising: receiving a file upload request and a corresponding upload file from a client end corresponding to a first user; searching for a personal online storage of the first user and a shared online storage of at least one related user of the first user; determining to upload the upload file to a partial online storage of the personal online storage and the shared online storage; and transferring the upload file to the partial online storage, wherein the first user belongs to at least one user group, users in the same user group are related users, the personal online storage of the first user and the at least one user group have a correspondence, and each user group has a sharing rule set, wherein the shared online storage provided by the at least one related user in the at least one user group is searched according to the sharing rule set of each user group and the correspondence between the personal online storage of the first user and the at least one user group, wherein when the first user belongs to more than one user group, the personal online storage is partitioned into a plurality of sub spaces, and in the personal online storage, each of the sub spaces is corresponding to one or more of the at least one user group, wherein a sub space among the sub spaces that is corresponding to multiple user groups has a priority when the shared online storage is searched according to the sharing rule set of each user groups.