The invention relates to a hippophae rhamnoides fruit juice composite beverage and a preparation method thereof. The hippophae rhamnoides fruit juice composite beverage comprises the following components in parts by weight of 20-30 parts of hippophae rhamnoides fruit juice, 30-45 parts of vegetable juice of which the Baume degree is 15-25, and 50-60 parts of soda water, wherein the NaHCO3 contentin the soda water is 0.4-0.9g/L. The preparation method comprises the following steps of blending the hippophae rhamnoides fruit juice, the vegetable juice and the soda water to obtain fruit juice first mixed liquid; and degassing the fruit juice first mixed liquid, performing sterilization, performing hot packaging and performing cooling so as to obtain the hippophae rhamnoides fruit juice composite beverage. The hippophae rhamnoides fruit juice composite beverage made by the method is uniform in color and free from layering, and miserable mouth feel of the hippophae rhamnoides fruit juice can be weakened.