Data writing method, memory controller and memory storage device

Disclosed are a data writing method, a memory controller and a memory storage device. The data writing method is used for writing page data in a rewritable nonvolatile memory module provided with a plurality of solid blocks, and each solid block is provided with a plurality of solid pages. The data writing method includes grouping the solid pages into a plurality of solid page groups according to speed of writing each solid page. The data writing method also includes compressing page datum into compressed data and calculating a data compression ratio of the compressed data. The data writing method further includes writing the compressed data in one solid page in the corresponding solid page group according to the data compression ratio.