使用螺旋相位板产生高斯涡旋光束时，要求光束中心与螺旋相位板中心对准重合。然而实际上光束中心总会在一定程度上偏离螺旋相位板中心，此时从相位板输出的光束即为离心高斯涡旋光束。对于传统的涡旋光束而言，暗核和质心为同一点，在传输中一直位于光束的中心位置。离心高斯涡旋光束则不同于传统的涡旋光束，对其传输进行了研究。研究结果表明，离心高斯涡旋光束的暗核和质心的位置分离，在传输过程中会发生移动。移动方向由拓扑电荷的符号确定，暗核的移动距离与拓扑电荷的大小无关，质心的移动距离则与拓扑电荷的大小相关。

While using the spiral phase plate (SPP) to produce Gaussian vortex beams, the center of the beam and the center of the SPP should be superposed. However, the center of the beam is always away from the center of the SPP to some extent in practice. The real output light from the phase plate are off-center Gaussian vortex beams. For conventional vortex beams, the core and the centroide are the same point and always located at the center during propagation. The off-center Gaussian vortex beam is different from the conventional vortex beams and its propagation is investigated in this paper. Research result shows that the core and the centroid of the off-center vortex beam are separate and moving during propagation. The directions of movement of the core and the centroid are decided by the sign of the topological charge. The movement distance of the core has no connection with the magnitude of the topological charge. However, the movement distance of the centroid is related to the magnitude of the topological charge.