Abstract: A method is proposed to design the computer software that is used to assure joint quality of resistant spot welding based on parameters monitoring and information processing.First, the requirement is analyzed for the monitoring and controlling system of the process and quality in the spot welding.And then software model of the sy stem is set up by mean of Unified Modeling Language. Secondly, according to the software model of the system and Rational Unified Process method used for software project design, a special software of the system is developed by Visual Basic 6.0 language. At last, application and test of the system shows that the performance of system is steady and the structure of software is logical. At the same time, the period of software exploitation is shortened and the software is good extensible.