The invention discloses a phase-changing and temperature-regulating blended yarn and a production process thereof. The components of the blended yarn comprise outlast fiber and cotton fiber, wherein the weight ratio of the outlast fiber is 10-50 percent, and the weight ratio of the cotton fiber is 50 percent. The production process of the blended yarn comprises the following steps in sequence: dyeing loose hair, mixing hair, shredding, blowing to form roller, carding, primary drawing, intermediate drawing, final drawing, roving, spinning and winding. Due to the blending of other types of fiber for spinning, the invention can solve the problem that the pure phase-changing and temperature-regulating fiber can not easily form the yarn, improve the service performance of the fabric, simultaneously reduce the cost, and increase the added value of the product.