The invention discloses a novel environment-friendly and green cotton-type fabric desizing method which comprises the steps of: (1) fully contacting a cotton-type fabric with an ionic liquid so as to desize the fabric with the ionic liquid and remove a sizing material, wherein the desizing is carried out in manners of impregnation, padding, cold-batch or combination of cold-batch and steaming; 2) completely washing the desized cotton-type fabric in the step 1); 3) recycling the ionic liquid from a mixture liquid generated during the desizing step by means of alcohols or water, and regenerating or recycling the sizing material; 4) recycling the ionic liquid or the alcohols from the mixture after the washing step 2) through distillation for recycling and reutilization. The desizing method, as well as a formula, are simple and are convenient to carry out. A desizing bath is free of addition of any chemical reagents, so that the method is free of wastewater discharge and avoids a problem of environment pollution due to desizing wastewater. After the desizing, the ionic liquid and the sizing material can be recycled.