The invention relates to the field of plate and strip rolling, in particular to a plate and strip leveling quality control method. According to a strip steel mechanical performance online detection and control method in the leveling process, firstly, a model input quantity and a model output quantity are selected and used, and a three-layer BP neural network model of the corresponding relation between leveling process relative parameters and strip steel mechanical performance is built; according to strip steel of a specific steel type, measured values of n groups of the leveling process relative parameters and measured values of strip steel mechanical performance parameters are collected and recorded to serve as training samples of the neural network model, learning and training are performed on a neural network by means of the BP method, and in other words, a mechanical performance forecast model of the strip steel of the steel type is obtained; by means of the mechanical performance forecast model, online control of strip steel mechanical performance in the leveling process is achieved. The leveling process parameters are adjusted according to the judgment result of a mechanical performance forecast value, online control of the strip steel mechanical performance parameters is achieved, and accordingly a strip steel material small in yield ratio can be obtained, and good forming performance of the strip steel is kept.