Abstract: Traditional polymeric photocatalysts are typically constructed using aromatic building blocks to enhance π-conjugation. However, their inherent hydrophobicity and rigid structure lead to poor dispersibility in aqueous solutions, resulting in significant optical losses and exciton recombination. In this study, two series of six novel polymer photocatalysts（FLUSO, FLUSO-PEG10, FLUSO-PEG30; CPDTSO, CPDTSO-PEG10, CPDTSO-PEG30） are designed and synthesized by incorporating the hydrophilic, non-conjugated polyethylene glycol (PEG) chain, into both the main and side chains of polymers. By precisely optimizing the ratio of hydrophilic PEG segments, the water dispersibility is significantly improved while the light absorption capability of the polymer photocatalysts is well maintained. The experimental results confirm that the optimized FLUSO-PEG10 exhibits excellent photocatalytic hydrogen evolution rate, reaching up to 33.9 mmol/(g·h), which is nearly three times higher than that of fully π-conjugated counterparts. Water contact angles and particle size analyses reveal that incorporating non-conjugated segments into the main chains enhances the capacitance of the polymer/water interface and reduces particle aggregation, leading to improved photocatalyst dispersion and enhanced charge generation.