Disclosed are a controllable phase change material package and a preparation method therefor and application thereof. The preparation method comprises the following steps: 1, performing surface treatment on a metal plate or bar so as to form a metal plate or bar with a rough surface, embedding into the surface a seed crystal powder which is used for inducing the nucleation of a phase change material, then placing the metal plate or bar in a sodium acetate solution, and placing the sodium acetate solution in a water bath for heat preservation to obtain a controllable trigger metal electrode (1); 2, mixing sodium acetate trihydrate crystal, water and a thickening agent, heating the mixture in a water bath and stirring until completely dissolved, thus obtaining a supersaturated phase transition heat storage solution, pouring the solution into a stainless steel metal ball (2), inserting the controllable trigger metal electrode (1) in step 1 and a conducting electrode (3), packaging, and finally placing in the water bath for heat preservation so as to obtain the controllable phase change material package. Based on the inherent supercooling defect of the inorganic phase change material, the controllable heat storage/release of supercooling phase change material is achieved, and the present invention has the advantages of simple preparation process, low equipment cost, short recycling period, stable heat release and the like.