Abstract: Aiming at the problems of traditional plastic products which are difficult to degrade and pollute the environment, this work selects environmentally friendly and degradable Jackfruit seeds starch (JFss), carboxymethyl cellulose (CMC) and sodium alginate (SA) as raw materials and prepares a biodegradable composite film by a coating process. The effects of the amount of JFss on the mechanical properties, water resistance, water solubility and moisture permeability of the composite membrane were investigated, as well as the changes of the wettability of the composite membrane with time, and the composite membrane was tested for soil burial degradability. SEM, FITR, XRD and TGA were used to characterize the morphology, structure and thermal stability of the composite films. The results show that the addition of JFss increases the tensile strength of the composite film by 35.8%, water resistance by 4.16%, water solubility by 7.8%, water vapor barrier by 153.7%, and has good wettability, moisture retention and biodegradability. In addition, each component of CMC, SA and JFss in the composite film forms intermolecular hydrogen bonds, which have good compatibility and thermal stability. The raw materials for the preparation of composite film by this method are inexpensive, simple to prepare, and can be produced on a large scale, which have potential applications in the field of biodegradable materials.