1. A Maximum A Posteriori (MAP) algorithm-based Turbo decoding method, an information symbol being sequentially divided into a plurality of sub-blocks, each sub-block comprising a plurality of sliding windows, the method comprising: iteratively estimating an information symbol by using an MAP algorithm, acquiring α and β boundary values for each sliding window and each sub-block by means of window boundary value inheritance and block boundary value inheritance, and recursively calculating posterior probability Log Likelihood Ratio (LLR) values of a whole window and a whole block according to the α and β boundary values; and performing decoding decision according to the LLR values.