Cassava flour has the potential to be used as a substituent of flour in making dry noodles. This study aims to obtain the optimum formulation of flour, hydrocolloid content and protein isolate content. Formula optimization of cassava noodle has been done by using two types of cassava flour: native and pre-gelatinization, adding additional food additives such as hydrocolloid (xanthan gum and konjac glucomannan) and pea protein isolate. The design of the formulation and optimization is done by D-optimal combined design method through Design Expert 7.0®. There are 31 different formulas for a test response that includes hardness, tensile strength, and cooking loss. Considering the three responses, the recommended optimum noodles formulation is based on pre-gelatinized cassava flour, 2% xanthan gum, 0% konjac glucomannan, and 4% protein isolate. The selected formula has water content, ash content, protein content, fat content, and carbohydrate content of 5.92%; 0.793%; 4.29%; 1,342%; and 87.025%. The level of consumer acceptance of texture, aroma, color, and overall parameters has a range of 3 (regular) to 4 (like). The optimum formula may be used for product development of cassava dried noodles.