The invention provides a
data compression method which comprises the following steps: obtaining an
original data sequence (N1, N2, N3,..., Nm); then obtaining a differenced data sequence (D1, D2, D3,..., Dm) according to an equality that k is greater than 1 and less than or equal to m and the
original data sequence (N1, N2, N3,..., Nm); and sequentially storing each differenced data in the differenced data sequence (D1, D2, D3,..., Dm). The invention also provides a data decompression method, a
data compression device and a data decompression device. By adopting the
data compression method, the data
compression method device, the data decompression method and the data decompression device, the differenced data sequence is obtained by carrying out back-minus-front computation on the
original data sequence, and each differenced data in the differenced data sequence is stored sequentially, because the value of the differenced data is less than that of the original data, the number of bytes for storing the differenced data is less than the number of bytes for storing the original data, thereby saving the data storage space.