The invention provides a preparation method of starch detection test paper in milk and milk solution and a detection method of starch; firstly, water solution containing alkali, iodide and oxidant is prepared, sufficiently dissolved and uniformly mixed, thus forming stable test paper iodine original solution; the test paper iodine original solution is uniformly fixed on a carrier by the forms of coating, printing or soaking and dried so as to obtain the detection test paper. The liquid to be detected together with the developer is dripped on the test paper; if the liquid to be detected contains matters such as dextrin, starch and the like, the color of the starch detection test paper changes to amaranth or navy blue, otherwise, the color of the starch detection test paper changes to alabaster to colorless; the qualitative or semi-quantitative detection of matters such as starch and the like can be carried out by matching with a colorimetric card for use; and the developer is acidic matter of 0.05-1mol/L in independent bottles. Compared with the traditional starch detection method, the detection method meets the requirements of simpleness, fastness and portableness; and simultaneously, the shelf life of the reagent is greatly prolonged.