NiGe/n-Ge Schottky barrier height is modulated by Ni/n-Ge reaction with 1 nm Al as an intermediate layer. The series resistance, barrier height and ideal factor of Schottky diodes are extracted by the forward I-V method, Cheung method and Norde method, respectively. Comparing with Ni/n-Ge SBD, the introduction of 1 nm Al insertion layer between Ni and Ge substrates can effectively reduce the barrier height and maintain stability between 350 ℃ and 450 ℃.