Summary: In view of the insufficient decision-making model for the test intervals before failing to make full use of the state test data and the inability of the fixed cycle test to guarantee the reliability during the test intervals, a test intervals decision-making model for condition-based maintenance is proposed based on real-time reliability, the relationship between component states in real time and real-time reliability established, and the range test interval is calculated based on equal failure risk, so the decision making is more in line with the reality. First of all, the real-time reliability of the component is calculated using a real-time reliability assessment method, and the contact of actual status and the reliability is established. On the basis of mastering real-time reliability and fulling using the historical information of the component, and the reliability curve is adjusted to make trend forecasting more accurately. Finally, the model is solved through failure risk constraint to ensure the safe operation of the component in the test interval period. An application example shows that the model can reasonably determine the next test interval, that the test interval is comparatively long to avoid waste when the failure rate is low, and that the testing is more and more frequent when the failure rate is increasingly higher in the latter stage. Therefore, this model is more realistic, and can meet the requirements of the condition-based maintenance.