The application discloses a failure rate determination method in an intelligent illumination system and the intelligent illumination system. The method comprises the steps of making an RTU lamp on-off scheme and a single lamp energy-saving scheme, issuing the schemes, executing the instructions in the schemes, issuing patrol measurement instructions, carrying out the patrol measurement, calculating an RTU total failure rate and the failure rates of various types according to the patrol measurement result data, etc. The intelligent illumination system comprises an intelligent illumination supervision center, a street lamp control module, single lamp controllers and street lamps. According to the schemes, the fine control of the street lamps is realized, the failure rates of different modes can be calculated according to the different demands, the vertical and horizontal comparison is convenient, a calculation process does not need the artificial participation, the labor cost and the time consumption are reduced effectively, a huge error brought by the artificial patrol measurement is also completely eradicated, and the failure rate determination accuracy and efficiency are improved substantially.