The invention belongs to the technical field of solar cells, and particularly relates to a linear perovskite solar cell and a preparation method thereof. The method comprises the steps of utilizing a stainless steel wire coated with a nanometer titania granular layer as an electrode, adsorbing perovskite active layer materials and hole transport layer materials, and finally wrapping a transparent carbon anno-tube grating as the other electrode to form the flexible woven coaxial linear perovskite solar cell. The open-circuit voltage, the short-circuit current density and the filling factor of the linear perovskite solar cell are 0.66 V, 10.2 mAcm<-2> and 0.49 respectively. The corresponding energy conversion efficiency is 3.3%. According to the linear perovskite solar cell, the transparent carbon nano-tube grating is used as the electrode, the solution dip-coating method is utilized for preparing an optical activity layer, the preparation technology is simple, the cost is low, the linear perovskite solar cell has the high strength and good flexibility, and the performance of the linear perovskite solar cell does not change along with changes of the incident light angle. According to a traditional weaving technology, the linear perovskite solar cell can be woven into a fabric or integrated into a garment, and can be used as a portable power supply device to be used in daily life of people.