A new cultivar of Miscanthus sinensis plant named ‘Red Zenith’ that is characterized by its exhibits a strong and vigorous plant habit, creating a v-shaped form tightly gathered at the base, its average plant height of 2 m, its foliage that is dark green in color with well-delineated white strips turning yellow striped in autumn, flowers that are vibrant red in sunlight with a pink sheen when young and fading to a paler red in late autumn, and its upright v-shaped flower tassels on thick peduncles.