Abstract: The traditional sample textile equipments have such problems as mechanical pattern,low automatic level and lack of connection among these equipments,for this reason,a sample textile CAD&CAM system was developed.This paper puts emphasis on network structure,function and communication protocol of sample textile CAD&CAM system.A single-master/multiple slave communication model based on RS 485 was studied and one to one master-slave communication was realized.In addition,the requested data packet,data packet and response package in communication protocol were defined and analyzed,and anti-interference design was discussed.Based on this communication protocol,the host of sample textile CAD&CAM system can transfer process parameters to a number of slave machines and monitor working state of slave machines.