The evolutionary cryptosystem is a new cryptosystem proposed by a Chinese researcher recently. This paper studies its security level resisting against multidimensional linear cryptanalysis in this paper. It is shown that the evolutionary cryptosystem possesses higher resistance than its initial fixed cryptosystem does for resisting against multidimensional linear cryptanalysis. Multidimensional generalizations of Matsui’s Algorithm 1 and Algorithm 2 based on log-likelihood ratio (LLR) statistics are introduced. By the relationship among the data complexity N , the bit advantage a and the success rate P S of these two multidimensional generalized algorithms, it is proven that more data is needed for attacking the evolutionary cryptosystem than that is needed for attacking its initial fixed cryptosystem when the bit advantage and success rate are identical. Moreover, it is shown that both time complexity and memory complexity for attacking the evolutionary cryptosystem are higher than that of attacking its initial fixed cryptosystem with the same data complexity. The research indicates that the evolutionary cryptosystem is more robust than its initial fixed cryptosystem against the multidimensional linear cryptanalysis. This evolutionary cryptosystem is a new cryptosystem proposed by a Chinese researcher recently. This paper studies its security level resisting against multidimensional linear cryptanalysis in this paper. It is shown that the evolutionary cryptosystem possesses higher resistance than its initial fixed cryptosystem does for resisting against multidimensional linear cryptanalysis. Multidimensional generalizations of Matsui’s Algorithm 1 and Algorithm 2 based on log-likelihood ratio (LLR) statistics are presented. By the relationship among the data complexity N, the bit advantage a and the success rate PS of these two multidimensional generalized algorithms, it is proven that more data is needed for attacking the evolutionary cryptosystem than that is needed for attacking its initial fixed cryptosystem when the bit advantage and success rate are identical. Moreover, it is shown that both both complexity and memory complexity for attacking the evolutionary cryptosystem are higher than th at of attacking its initial fixed cryptosystem with the same data complexity. The research indicates that the evolutionary cryptosystem is more robust than its initial fixed cryptosystem against the multidimensional linear cryptanalysis.