Plastics that are used as packaging have many advantages including flexible, transparent and not easily torn. The disadvantages of the material used in the manufacture of conventional plastics are non-biodegradable in the environment. One of the ingredients for making biodegradable films is white sweet potato, this is because chemically, sweet potato has amylose content of 35.99%. Native biodegradable starch films have hydrophilic properties, to overcome these weaknesses, it is necessary to repair or modify starch. Biodegradable hydroxypropylationcrosslinking films have a lower solubility value than unmodified films. High film solubility values indicate a decrease in the quality of the film to be used as food packaging material because the film easily dissolves in water and increases the possibility of damage to packaged products especially for products easily affected by water content. The tensile strength and percent elongation values of the entire modified starch films have a higher value than those of natural sweet potato starch films. Water vapor transmission rate (WVTR) is lower than that of natural sweet potato starch films. Transparency value has decreased to 13.89-14.10 (%abs/mm) which indicates that the film is in good clarity.