The evaluation of equipment system performance reliability is one of the most important items in the reliability evaluation work of the armament products. In the past, few consideration is given to the problem whether the radar equipment system working performance can reach the requirement or not, while evaluating the radar reliability of working performance (RWP). This paper shows that the problem of the equipment reliability is a basic starting point in the evaluation of radar equipment system performance reliability and defines the reliability in performance of radar equipment system. According to the limitation of the using condition, the reliability in performance of radar equipment system is defined as a narrow sense working performance reliability and a broad sense working performance reliability. Through the analysis of the radar equipment system performance reliability, we get to know that the radar equipment system reliability is a parameter to tell how long the radar equipment performance can hold on, and an important guide line in evaluating the radar equipment efficiency. In this paper, the evaluation of the performance reliability of new type radar equipment system is carried out from both the narrow sense working performance reliability and the broad sense working performance reliability, and an evaluation model of the new type radar equipment system working performance based on the narrow sense RWP and broad sense RWP is given, which can provide a scientific basis for the equipment maintenance decision-making and the establishment of related maintenance strategy.