Herein, the in‐orbit performance of the solar array for Chang'e‐4 Relay Satellite in an Earth–Moon Lagrangian point 2 (EML2) Halo orbit is analyzed. The daily degradation coefficient of the photovoltaic current is calculated to be 0.99989 independent of whether the relay antenna outspreads, indicating an annual degradation coefficient of 3.94%. However, due to the shading effect of the antenna and the electrical performance degradation, the output voltage of the solar array dissatisfies the requirement of the power controller on around the 700th day, resulting in an abrupt decrease of the photovoltaic current. In addition, the in‐orbit working temperature of the solar array for Chang'e‐4 Relay Satellite is also studied. The working temperature mainly ranges from 52.3 to 76.8 °C, while the working temperature decreases to the range of 0–25 °C once the relay antenna outspreads. The present work is helpful to a deepen the understanding of EML2 Halo orbit and provide reference to the solar array design for a deep space exploration aircraft.

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