The effect of proton irradiation on electrical characteristics of high-voltage (3 kV) 4H-SiC junction diodes have been investigated. The diodes were irradiated through 10-µm thick Ni-film. The energy of protons and irradiation dose were 2.8 MeV and 4×1011 cm-2, respectively. After proton irradiation, the diodes exhibited 35-% increasing in on-state resistance, about 3 times decreasing in the reverse recovery charge with the reverse recovery character being "hard".