The invention provides a method which can avoid downloading identical mails repeatedly when a pop3
post office protocol is used. The method comprises the following steps: S1, through a UIDL command, an independent ID assigned to the mails by a mailbox
server for the current mails to be downloaded; and the ID number is recorded; S2, the time tag of the mail is recorded; S3, when a user receives the mail again, firstly, the independent ID number of the mail to be downloaded is inquired by using the U1DL command, and the the independent ID number is compared with the independent ID number of each mail reserved at local, if an identical ID number does not exist, S6 is performed, and if the identical ID number exists, S4 is performed; S4, the time-tag of the current mail is obtained by using a TOP command; S5, the obtained time-tags and the time-tags of the identical ID number are compared one by one, if the time-tags are identical, the downloading of the current mail is given up; and if the time-tags are different, S6 is performed; S6, the current mail is downloaded. The method of the invention has the advantages that weather a mail to be downloaded is loaded or not can be judged, and thereby the receiving time is reduced greatly, and the
network data flow is also reduced greatly.