The invention provides a silicon carbide MOSFET device and a manufacturing method thereof. The device comprises a drain electrode metal unit, an N+ substrate, and an N- drift region. And a groove is formed in the N- drift region. Besides, the manufacturing method includes: a groove is etched in an epitaxial wafer, wherein the groove and a lithography aligning mark are formed simultaneously; polysilicon is deposited on an N- epitaxy unit and etching is carried out to form an ion implantation barrier layer pattern; aluminium ion implantation is carried out by using the polysilicon as a mask to form a P type base region; silicon dioxide is deposited and back etching is carried out to form a side wall, and nitrogen ion implantation is carried out by using a self-aligning technology to form an N+ source region; the polysilicon and silicon dioxide are removed, and polysilicon is deposited and an ion implantation barrier layer pattern is formed; aluminium ion implantation is carried out to form a P+ contact region; and the polysilicon is removed, ion implantation activation annealing and gate oxide oxidation are carried out. According to the invention, the channel self-aligning technology is realized and the depth of the P+ contact region is increased, so that the starting of the parasitic BJT transistor is suppressed effectively and the anti-UIS failure capability of the silicon carbide MOSFET device is enhanced to a certain extent.