A computer-based method for controlling product quality is disclosed. The method includes the steps of: detecting whether a quality of raw materials bought from at least one supplier are acceptable; detecting whether a quality of using materials used at a processing procedure are acceptable; detecting whether a quality of products being manufactured at the processing procedure are acceptable; receiving and storing a post-procedure report obtained by sampling the products after the processing procedure; repeating steps of detecting materials used at a processing procedure, detecting products being manufactured at the processing procedure, detecting the sampling products after the processing procedure, and completing the manufacturing if all the products are finished. A related system is also disclosed.