Abstract: Main technical performance requirements of RS-485 bus cables for communication in the 90 ℃ tower solar photothermal power generation mirror field were introduced. Material selection and production process control of the cross-linked polyethylene insulation heat-resistant RS-485 bus cable for communication in the 90 ℃ tower solar photothermal power generation mirror field were elaborated. Through structural design and calculation examples of the main electrical performance of RS-485 bus cable for tower solar photothermal power generation mirror field communication, key parameter design, testing principles and testing methods were explained. The RS-485 bus cable for tower solar photothermal power generation mirror field communication was also tested. Results showed that actual measured values met design requirements, satisfied the demand for RS-485 on-site communication in tower solar thermal power generation mirror field, which could have broad application prospects.