The invention relates to a preparation method for cigarette paper with functions of supporting combustion and reducing a CO emission amount. The preparation method comprises the following steps: processing a cellulose raw material by combining a chemical method and a high-pressure homogenizing method to prepare a pure plant nano-fibre combustion supporting agent (functional nano-fibres); then, mixing the obtained nano-fibre combustion supporting agent and pulp of papermaking cigarette paper, or performing coating/sizing the nano-fibre combustion supporting agent dispersing solution on the surface of commercial cigarette paper to prepare nano-fibre combustion supporting agent-modified cigarette paper. The cigarette paper which is modified through the pure plant nano-fibre combustion supporting agent provided by the invention has good functions of supporting the combustion and reducing the CO emission amount; the prepared cigarette paper has higher smoldering velocity compared with thatof common cigarette paper; the CO emission amount is remarkably reduced; combusted ash is grey; the cigarette paper is good in appearance, can be used producing high-quality cigarette, and can reducethe damage to human body health.