Facing the saturation of global plastic products, people pay more and more attention to environmental protection. New environmentally friendly degradable compost materials have been applied in various fields in recent years. As the largest accessory of mobile phone accessories, mobile phone case is made of PLA degradable materials. On the one hand, it protects mobile phones and on the other hand reduces the waste of materials. After more than a year, the design scheme of this protective cover has been modified three times to avoid the brittleness of materials, and constantly adjust the mold to finally achieve the anti-fall effect of this special material.