在实际的高功率激光系统中，当光学元件非共轴放置、光学元件有像散特性、光束倾斜入射时，系统中会出现许多离轴的鬼点，鬼点也可能变为鬼线。采用4×4光学矩阵，给出了计算高功率激光装置中的任意n阶离轴鬼点或鬼线的方法，还给出了判断鬼点或鬼线虚实的判据。

In a practical high power laser system, it may happen that all optical elements do not share the same axis, some optical components may show certain astigmatism, and laser beams may be deliberately arranged to incident at non-zero angles to the optical axis. In this work, using the 4×4 optical matrices, the method for locating the off-axial ghost points (or ghost lines) of various orders in high power laser system have been given. In addition, practical criterions of specifying real and virtual ghost points (or ghost lines) have been put forward.