The main purpose of this thesis is to inrestigate the which conditions may affect the quality of the welds during the operating process. To find out which conditions may affect the weld’s quality, we had used standard process from a model company to discuss product quality control. First, we use the Taguchi methods to classify experimental parameters, e,g, signal factor, control factor, interference factor, and then we use the orthogonal array to arrange all factors. Starting the welding operation with parameters in the orthogonal array and collect all results from welding test, we use the collection of parameters from previous method to calculate the total value, average value and weld quality’s error value.