The invention discloses a treatment graph conversion method based on an adjustable spiral line type laser spot, and the method comprises the following steps: S1, selecting a reference treatment laser beam outputted by a carbon dioxide treatment machine, and selecting a focus lens and a treatment head which are matched with the reference treatment laser beam; s2, arranging a light spot conversion device at the output end of the reference treatment laser beam; s3, correspondingly controlling a light spot conversion device through a microprocessor in the carbon dioxide therapy machine, so that the reference therapy laser beam passing through the light spot conversion device is converted into a spiral line type laser spot with a proper size, the spiral line type laser spot sequentially passes through the graph scanner, the focus lens and the treatment head to generate a treatment graph matched with a treatment part of a patient. According to the method, the treatment light spot output by the final device is spiral, the size of the treatment light spot can be freely adjusted, a focus lens or a treatment head does not need to be replaced, operation is easy, and cost is low.