In the information security area, traditionally m-sequence is used as the base sequence on which non-linear combination, non-linear filtering and non-uniform sampling are applied to generate a sequence with high linear complexity. Yet the stability of linear complexity of such a sequence is not satisfactory. In this paper, we propose m-subsequence which is generated by changing the state transition order of the m-sequence. Since the m-subsequence is made by changed the order of the m -sequence, it is a non-linear sequence. The linear complexity is shown to be stable and exponential in the length of the shift register by testing data. In addition, the k-error linear complexity remains the same as the length of the shift register grows.