The invention belongs to the field of welding machining, and discloses a welding line forming quality monitoring method. The method comprises the following steps that a, initial data are obtained by collecting welding parameters and welding line forming situations; b, an initial BP neural network model is constructed and subjected to training, and a final BP neural network model is obtained; c, the relational expression among the welding parameters, feature parameters and the welding line forming situations is constructed to serve as a predicting display model; and d, real-time welding parameters during welding line forming are collected and input into the predicting display model, and the needed real-time welding line forming situation is obtained. Through the welding line forming qualitymonitoring method, through real-time measurement of welding current, voltage, speed and the wire stretching amount, the welding line forming situation is objectively evaluated in real time, and imaging display is conducted. Accordingly, the subsequent technology can be guided in time, the quality is improved, losses are reduced, and danger is avoided.