The invention relates to an automatic filter pulley switching mechanism with a high-precision flexible positioning system. A filter pulley is driven by a power system to work by virtue of a grooved pulley system. The automatic filter pulley switching mechanism is characterized in that a drive way between the power system and the filter pulley is as follows: a synchronous pulley I and a synchronous pulley II are driven by the power system to rotate by virtue of a motor speed reducer; the synchronous pulley I and the synchronous pulley II are transmitted by adopting the power of the synchronous pulley to form flexible power transmission; and the grooved pulley roller crank is driven by the synchronous pulley II to rotate, a notch in the filter pulley is shifted by the grooved pulley roller crank to enable the grooved pulley to rotate so as to switch filter pulley pieces. The automatic filter pulley switching mechanism is high in transmission precision; the filter pulley is convenient and rapid to disassemble, and no damage risk exists. Since the filter pulley is convenient to disassemble, no obstacle exists; and a grooved pulley mechanism is matched with a flexible positioning ring having a certain pre-tightening force, so that the stability in rotation is realized, and the positioning precision is high.