A method for updating the position of electronic price tag by graphic code including: step 1, placing a plurality kinds of commodities on a commodity shelf, mounting an electronic price tag screen on the commodity shelf and below the commodities; step 2, displaying at least n position graphic codes with an even interval on the electronic price tag screen; step 3, carrying out a first scan to send the commodity information to a server; step 4, carrying out a second scan to check a position of the commodity; step 5, sending a plurality of size graphic codes with different size information to a position where the position graphic code in step 4 locates; step 6, selecting a size graphic code with a proper size for a third scan by the supermarket tally clerk; step 7, generating a commodity tag by the server.