The invention discloses a low-temperature-resistance PP-R solar outdoor pipe and a preparation method thereof. The low-temperature-resistance PP-R solar outdoor pipe is prepared from the following rawmaterials in parts by weight: 50 to 70 parts of PP-R, 10 to 15 parts of PP-B, 2 to 3 parts of poly butylenes succinate, 5 to 6 parts of nano SiO2, 1 to 2 parts of starch, 6 to 7 parts of long-chain branched polypropylene, 1 to 2 parts of maleic anhydride-styrene copolymer, 4 to 5 parts of sorbitol, 1 to 2 parts of beta crystal form nucleating agent, 8 to 9 parts of dimethyl phthalate and 1 to 2 parts of formamide. According to the low-temperature-resistance PP-R solar outdoor pipe disclosed by the invention, surface loaded beta-nucleating agent modification is performed on inorganic particlesin color master batch, and meanwhile PP-B is added to induce crystallization to prepare a PPR pipe with a high beta crystal content; compared with the prior art, a beta crystal crystallization effectis remarkably improved, and the problem of low temperature fragility of the PP-R pipe is solved.