Solar energy calculation aims at calculating solar radiation collected by a solar receiver using solar geometry and radiation data. The essential calculation includes the incident angle of solar rays on the receivers and the projection angle of solar rays on a specific plane, although the calculation procedure quite differs due to the receiver differences in structure, orientation as well as optical characteristics. To date, the spherical coordinate system is taken as the basis for describing the law of solar motion and related calculation. However, such a conventional method makes the calculation process complex. In this article, taking the fixed and tracked solar panels as case studies, it is analyzed in detail that how to use vector algebra for coordinate transformation, how to select and establish coordinate systems, and how to use vector algebra to analyze the spatial angle relationship between line and line (plane) as well as the spatial transmission law of solar rays after mirror reflection. The analysis results show that the calculation process of the incident angle of solar rays on fixed and tracked solar panels as well as the projection angle of solar rays on a specific plane can be greatly simplified by selecting and establishing a reasonable coordinate system according to actual needs, and vector algebra is very suitable for analyzing the three-dimensional transmission process of solar rays within a reflective linear solar concentrator.