The invention discloses a purification process of tetracycline. The purification process comprises the following steps: 1) preparing a tetracycline crude product: conducting fermentation cultivation of streptomyces aureus spores in a fermentation tank, adding oxalic acid and conducting acidifying treatment; conducting filtration so as to obtain a filtrate, adding calcium salt to the filtrate under an alkaline condition, conducting precipitation, and conducting acid pickling on a precipitate so as to obtain the tetracycline crude product; 2) drying the tetracycline crude product; 3) preparing a tetracycline-inorganic salt dissolved solution, namely, dissolving the dried tetracycline crude product by virtue of a saturated inorganic salt solution, so that the tetracycline-inorganic salt dissolved solution is obtained; and 4) precipitating the tetracycline-inorganic salt dissolved solution, namely, dropping ammonia water to the tetracycline-inorganic salt dissolved solution to regulate pH value to 3-5, decreasing temperature to 0-10 DEG C, keeping the dissolved solution for 1-2h until a tetracycline-inorganic salt precipitate is separated out, and then sequentially conducting vacuum filtration and vacuum drying treatment, so that a finished tetracycline product is obtained. The purification process provided by the invention has fewer steps, so that the loss of the tetracycline in a purifying process is reduced.