Temperature data acquisition system into the one thing that is very important in industrial activity, because it is a fraction of a control process. With regard to the importance of the system, then do the design of the temperature data acquisition system capable of conducting monitoring the temperature of a plant. To be able to design the system was first carried out the process of converting the temperature into an analog voltage using a temperature sensor LM35. After going through the process of conditioning an analog voltage signal is converted into digital data using the ADC. Digital data obtained and processed by the microcontroller ATMEGA8535 and displayed, so we get a plant with information about the temperature unit ° C on an LCD and PC. From the design of the temperature data acquisition system showed that this system has the ability to measure the temperature of 20 º C to 80 º C with an average error of 0.1 designation temperatures. and the success rate of 99%.