Plastic is one of the materials that is often used in everyday life. One of them is the use of food and beverage packaging products that use plastic as the main ingredient. Because of this great opportunity made a motivation in the manufacture of a plastic bottle molding machine, namely the blow molding machine. In the blow molding machine, there are mold components that have an important role to form a bottle preform into the desired bottle shape, therefore the process of designing the mold in a blow molding machine with a volume capacity of 300 ml must be taken into account the dimensions and determination of the material accurately, because it will be very determine whether the product's final product has a product defect or not. Mold design in a 300 ml blow molding machine has a simple and economical design. With dimensions of length 150 mm, width 50 mm, and height of 180 mm, using 5xxx Series Aluminum material with modulus of elasticity 69 GPa and 201 thermal conductivity (w / mK) suitable for machining processes with a total cost of material and machining Rp. 6,500,000 .00. Mold design results also get supporting components such as back plates, pins, pulling levers, and clamping systems to assist molds during the production process. Components such as pulling lever, back plate, and clamping system use the same material, namely the A36 or JIS 3101 ship plate which has strong physical properties and is very good for welding, while for the pin it uses aluminum a mixture of aluminum household appliances and motorized spare parts melted down. This design also gets results in the form of the thickness of the average product bottle after being blown with a thickness of 0.6 mm, the pressure required 7 bars, and clamping