We have developed a turbo codes module for zero field MAMMOS and a simulation system to examine the performance of a turbo codes module for the zero field MAMMOS readout signal. In the zero field MAMMOS readout channel, issues such as dropouts and edge-shifts may determine the bottom of the error rate when the recording density reaches a certain height, and also reduce the performance of turbo codes. In order to improve the performance of turbo codes to deal with these issues, we propose an improved turbo codes. We first confirmed the performance of the turbo codes module, simulated for the additive white Gaussian noise channel modesl, and then we investigated the performance for the zero field MAMMOS readout channel. With respect to code rates and number of iterations, the turbo decoding results of zero field MAMMOS readout channel against the conventional binarization method are presented. Finally, we present the performance of improved turbo codes and confirm the effectiveness of the improvement.