Abstract: In order to solve the problem of flash break-off of PROFIBUS-DP network in tobacco primary processing line, the structure of the PROFIBUS-DP network in tobacco blending and cutting section was improved as following:inspecting the communication cable shield of PROFIBUS-DP to ensure that it was multipoint earthed; tightening or replacing the terminals in PROFIBUS-DP; normalizing the wiring of PROFIBUS-DP communication cable to reduce mutual interference; dissecting PROFIBUS-DP network with repeaters to reduce the interactions between substations. The results of application showed that after improvement, tobacco blending and cutting section ran stably, the number of PROFIBUS-DP network stoppage reduced from average 3 times/month to 0, the reliability and resistance of the network to disturbance were promoted.