Abstract: For spacecraft products after long-term storage in specified ground environment, it is necessary to establish a set of effective method and system to evaluate the performance and the reliability of the stored product. so as to provide a basis for the decision-making of product reuse or deprecation. Based on the principles and methods of system engineering, the evaluation factors such as the product performance and application status after long-term storage in the specified ground environment are sorted out. According to the demand from the customer and the quality & reliability requirements of the spacecraft product, an evaluation system consisting six elements various dimensions and multi-levels, from technological and managerial aspect respectively, is established for assessing the spacecraft products in long-term storage environment. Through the practice of evaluating a certian satellite product which have been stored for more than six years, the above-mentioned technical method and the management mode for assessing the product condition are well implemented, to support the final decision of reusing the product.