针对连续变量量子密钥分发（CVQKD）通信距离较短的问题，在多维数据协调方案的基础上，利用连续密度进化和差分进化方法，设计出优质度数分布的低密度奇偶校验(LDPC)码，并提出LDPC码码字重复方法，进一步提高多维数据协调的效率，有效地降低了收敛信噪比，延长了信息传输距离。实验仿真结果表明：在分组码长为106时，收敛信噪比能够降低至-6 dB以下，协调效率可达90.27%，提取到的安全密钥量为0.22 kb/s，信息传输距离超过80 km，该方法可有效延长CVQKD系统的通信距离。

For the problem of short communication distance in continuous-variable quantum key distribution (CVQKD) protocol and on the basis of multidimensional reconciliation scheme, the low-density parity-check (LDPC) codes with good degree distribution are designed using a continuous density evolution and differential evolution method. The method of repeating LDPC codes is proposed as well, which further improves the efficiency of multidimensional data coordination, effectively reduces the convergence signal-to-noise ratio threshold and extends the secure range of communication distance. The simulation results indicate that when the block length is 106, the convergence signal-to-noise ratio can be less than -6 dB, and the data reconciliation efficiency can achieve 90.27%. The amount of the extracted secure secret key is about 0.22 kb/s, and the secure range of communication distance exceeds to 80 km, which means the distance can be effectively extended in CVQKD system.