Abstract: A noise robust voice conversion algorithm based on joint dictionary optimization is proposed in this paper to solve the problem that it is difficult to effectively convert noisy source speech into the target one.In the composition of the joint dictionary,the speech dictionary is optimized using a backward elimination algorithm.At the same time,a noise dictionary is introduced to match the noisy speech with the joint dictionary.The experimental results show that the backward elimination algorithm can decrease the number of dictionary frames and reduce the amount of calculation while ensuring the conversion effect.In low SNR and multiple noise environments,the algorithm has better conversion effect than the traditional NMF algorithm and the NMF conversion algorithm plus spectral subtraction de-noising.The proposed algorithm improves the robustness of the voice conversion system.