The invention relates to the technical field of street lamps and discloses a solar street lamp capable of moving transversely. The solar street lamp comprises a base, wherein a telegraph pole is inserted into the middle section of the upper surface of the base; a sliding device is fixedly mounted at the bottom of the front surface of the telegraph pole; clamping plates inserted into the bottom ofthe telegraph pole are fixedly mounted inside the base; sliding grooves are formed in two ends of an inner cavity of the base; transverse plates connected with the telegraph pole are movably mounted inside the sliding grooves; rotating columns positioned outside the sliding grooves are in threaded connection with the upper surfaces of the transverse plates; and screw blocks connected with the upper surface of the base are fixedly mounted at the ends, positioned outside the base, of the rotating columns. The invention further discloses an adjusting method of the solar street lamp. The solar street lamp and the adjusting method have the advantages that through the mounting of the clamping plates inserted into the bottom of the telegraph pole inside the base, the telegraph pole can be more stably mounted inside the base, and the safety can be improved; and through the mounting of the transverse plates and the rotating columns, the telegraph pole can be more fixedly mounted inside the base, and the high safety performance can be achieved.