An In04Ga06N/GaN homo-heterojunction IMPATT diode was proposed. Due to the immature P-type GaN manufacturing process, this research scheme could be taken as an alternative scheme for GaN based IMPATT diode. For comparison, the DC and AC characteristics of both In04Ga06N/GaN heterojunction IMPATT and PN junction IMPATT diode were studied in detail. The results showed that the performance of In04Ga06N/GaN IMPATT diode was better than that of traditional PN junction IMPATT diode without P-type GaN.