A silicon carbide crystal and a manufacturing method thereof are provided. The silicon carbide crystal includes an N-type seed layer, a barrier layer, and a semi-insulating ingot, which are sequentially stacked and are made of silicon carbide. The N-type seed layer has a resistivity within a range of 0.01-0.03 Ω·cm. The barrier layer includes a plurality of epitaxial layers sequentially formed on the N-type seed layer by an epitaxial process. The C/Si ratios of the epitaxial layers gradually increase in a growth direction away from the N-type seed layer. A nitrogen concentration of the silicon carbide crystal gradually decreases from the N-type seed layer toward the semi-insulating ingot by a diffusion phenomenon, so that the semi-insulating crystal has a resistivity larger than 107 Ω·cm.