A blue phase liquid crystal display device and a manufacturing method thereof are provided. The blue phase liquid crystal display device includes a plurality of pixel units arranged in a matrix, the blue phase liquid crystal display device including: a first substrate and a second substrate arranged opposite to each other, and a blue phase liquid crystal layer arranged between the first substrate and the second substrate. Each of the pixel units includes: first protrusions located on the first substrate; pixel electrodes covering the first protrusions; second protrusions located on the second substrate; and common electrodes covering the second protrusions.