The invention relates to yoghurt powder, a preparation method of the yoghurt powder and a method for preparing the yoghourt by using the yoghurt powder, and aims to solve the problem that a gel or a thickening agent is added to yoghourt soled in the market and eaten by consumers at present. The yoghurt powder is made of whole milk powder, skim milk powder, lactic acid bacteria, sweet burdening and auxiliary materials. The preparation method of the yoghurt powder comprises the steps as follows: I, weighing, II, pre-mixing and III, mixing and packing. The method for preparing the yoghourt comprises the steps as follows: a), preparation of a mixed solution and b), fermentation. According to the yoghurt powder, the preparation method of the yoghurt powder and the method for preparing the yoghourt by using the yoghurt powder, the preparation methods are simple, no food additives are required to be added to food, cold chain transport is not required, the quality is easy to control, and large-scale production can be realized. The methods are used for preparing the yoghurt powder, and the yoghurt powder is used for preparing the yoghurt.