Disclosed is a WWW-based POS with both consumer self-service ordering and billing functions. A network connected device is connected online with the WWW-based POS of a web server, and a browser is provided as an interface to execute the WWW-based POS, and the WWW-based POS provides a cashier ordering and billing interface and a consumer self-service ordering and billing interface, so that the WWW-based POS has both functions of the cashier ordering and billing interface and the consumer self-service ordering and billing interface at the same time, and can switch from one to another according to actual requirements and conditions.