The invention discloses a preparation method of an adhesive self-thickening supporting agent. The preparation method comprises the following steps: preparing a saccharose solution; washing or picklinga supporting agent; putting the supporting agent in the saccharose solution to be soaked and aired till the water content is 3-5wt.% to obtain a wet supporting agent; uniformly mixing the wet supporting agent, a coating material and a dispersant; fishing the supporting agent treated in the step out to be dried; grinding the supporting agent; and screening the supporting agent. Compared with an existing way of preparing a fracturing liquid, the self-thickening supporting agent can be prepared online in a construction well site, so that the operating cost of well site equipment and transportingvehicles is lowered. Moreover, the type and amount of the coating material are selected and controlled according to the fracturing oil deposit temperature and degree of mineralization of injected water, so that the oil deposit adaptability of a self-thickening supporting agent fracturing construction technology is improved greatly.