ZigZag-decodable (ZD) codes, as a type of erasure codes, are designed and generated based on the ZigZag decoding algorithm. They only require a small computation overhead to repair failed data in the storage system but need to store more redundant data than other erasure codes to ensure the high reliability of the system. To reduce the storage overhead generated by the ZD codes, this study proposes an optimized ZigZag decoding algorithm by analyzing the idea of ZigZag decoding currently used in storage systems. The new decoding algorithm can make full use of the information in the parity data to repair data. This study also proposes a new ZD code encoding scheme based on the new decoding algorithm. Due to the higher information utilization of the new algorithm, the new encoding scheme can satisfy the high reliability of the storage system with less storage overhead. The experimental results show that the new ZD code encoding scheme proposed in this study has the optimal storage overhead, and the decoding and encoding performance is much higher than that of the widely used RS code.