When the area of concrete beams and concrete columns strengthened by the method of enlarging the crosssection is small, the coarse aggregate is usually hard to be injected the strengthening area and the concrete is also difficult to be vibrated. Thus, a new strengthening technology named strengthening technology by grouting in the welding closed steel template is proposed in this paper, which firstly assembles the steel outside the original components, secondly sets the steel templates and lastly pours the cementbased grouting material. This strengthening technology is characterized by using the cementbased grouting material and welding closed steel template to replace the traditional concrete and traditional templates. It has already been applied in two applications which are presented in this paper, and the result shows that it can be easily applied in the structural applications, and it can save construction time considerably, and make the construction process more convenient.