While resistance spot welding (RSW) has been the most successful sheet metal joining process in automotive industry, there are still certain quality and reliability issues due to the control system and its application process. Some weld spots have hard-to-reach areas and new materials make the process more complicated resulting in new challenges for quality welds. Recently, a new welding machine called one-sided RSW was introduced to make a weld of hard-to-reach areas in automotive application. Intelligent current regulation algorithm of welding machine timer helps to control welding current and time with more stablility than conventional constant current regulation. Newly developed RSW simulation tool is another advanced technology to improve weld quality and production stability. In this research, advanced RSW technologies, including one-sided RSW, intelligent adaptive control, and simulation of RSW process, are discussed with various automotive applications.