Design of the intelligent sensor is an important job of the networked control system.The technologies of multiplex and cross-lays are applied in the model of TCP/IP

based on which the design method and process of intelligent sensor are presented.With the technology of multiplex

multi-protocols of transfer lay are achieved.With the technology of cross-lays

the applications of UDP/TCP are achieved in a field device called intelligent sensor

which is usually used among computers.In the experiment

tests and comparisons are done for the real-time property and multiplex effect of UDP/TCP

which show the feasibility of multiplex and the difference of the real-time property with different protocols.And it also confirms the feasibility and validity of the designed method.