Abstract: To solve channel features extracted by the two communication parties was significantly different, resulting in a low key generation rate and consistency, a key generation scheme based on cyclic grouping of difference thresholds (TGKG) was proposed. First, the Channel State Information (CSI) was grouped with a threshold such that the interval of data within the group was greater than the threshold to reduce quantization error and hence key disagreement rate. To avoid inconsistent grouping due to data errors, circular grouping was performed on one side only. Meanwhile, the scheme was applied to quantize real part and imaginary part of CSI, respectively, which can significantly increase key generation rate. The effectiveness of proposed scheme in terms of key disagreement rate, key generation rate and security was proved by probabilistic and information theoretic formulas. The experimental results show that the key disagreement rate of proposed scheme for both communicating parties is about 2%, and the key generation rate is about 142% under the condition of 5dB.