In order to solve the problems that the domestic weighing equipment is low in automation and difficult to manage, a set of weighing systems is designed. In this weighing system, the lower machine, being AT89S51, uses the RS485 bus transmission pressure signal to realize primaryslaver multi-computer communication. The upper machine, being PC, uses the TCP/IP Network Protocol to transmit the received data to central server. To guarantee the safety of data transmission, it adopts DES algorithm to encrypt and decrypt the data. Finally, in the development environment of MyEclipse6.5, it develops a weighing information management system with Java language based on C/S mode.