The invention discloses a method for preparing an optical cable for a smart power grid. On the premise that the fire-resistant and insulation principle of the ceramic silicone rubber is not changed, the organic rubber is removed and the formula of inorganic powder is optimized; and the fire-resistant and insulation layer carries out sintering and porcelainizing reaction at a high burning temperature and a compact sintering ceramic case with low porosity is obtained, so that the high-temperature insulation and fire resistance of the optical cable and the power core at a high burning temperature can be improved obviously. Moreover, an outer basalt fiber cloth cover has the flexible texture; before powder pouring, the free end of the outer basalt fiber cloth cover turns over outwardly and exchange of the inner surface and the outer surface is realized; a die tube is used for cooperation and a short to-be-smashed space is formed in the die tube, so that a smashed tube can go in or out of the die tube successfully to carry out smashing and pulling or rolling can be avoided after completion of the smashing. Therefore, the time and effort can be saved; the production process can be simplified; lots of costs can be saved; and the manufacturing length of the optical cable is not restricted theoretically.