In this research , senior middle school students were examined respectively in 2 experiments, applying 2×2 between-group design. It aimed to investigate the influence that text signals have on different students of different types of problem posing when reading so as to verify the working mechanism of text signals. Conclusions were as follows. In the first experiment, after the addition of the variable with the name of types of problem posing the qualitative hypothesis of text signal was tenable while the quantitative hypothesis, which was very complex, was only tenable under certain circumstances. In the second experiment, the mechanism of the effect of text signals supported the strategy-switch hypothesis more.