The invention discloses a polysemantic digital image retrieval method based on representation conversion. The method comprises the following steps: firstly, users select query images from the prior multi-mark image library, including relevant images and irrelevant images; secondly, polysemantic information which is implicated in the query images is described explicitly by means of representation conversion; thirdly, a forecasting model is obtained after study of the query images after conversion by adoption of a preset classification method; fourthly, concept marks of the images waiting for retrieval in a digital image memory device are forecasted on the basis of the forecasting model, and retrieval is performed by utilization of forecast results and the retrieval images are returned; fifthly, if the users are satisfactory with retrieval results, the sixth step is executed; if the users are not satisfactory with the retrieval results, more query images are selected from the multi-mark image library for feedback, and the second step is executed; sixthly, the operation is finished. The polysemantic digital image retrieval method based on representation conversion explicitly processes polysemantic information of the images on the basis of the representation conversion technology and solves the problem that a majority of the prior image retrieval methods can only process monosemantic images.