We make a critical review on the recent reported surface strategies of g-C3N4 toward enhancing water splitting performance, focusing on the theoretical basic and strategy-activity correlation. Display omitted •The basic of photocatalytic water splitting is presented.•The advanced surface strategies are classified and discussed.•The recent progress of surface strategies on g-C3N4 for water splitting is reviewed.•A brief conclusion is given and the remaining challenges for artificial photosynthesis are outlooked. Photocatalytic water splitting based on particulate photocatalysts offers a scalable pathway to generate hydrogen fuels while also mitigating environmental crisis. To establish high-efficiency photocatalytic system, strategies based on the modification of the host photocatalyst surface hold the key to affect the adsorption/activation ability of reaction molecules, and the efficiency of charge transport. As one type of layered conjugated polymer materials, graphitic carbon nitride (g-C3N4) has recently attracted extensive scientific interest in this research area owing to its unique structure and fascinating properties. However, the efficient water splitting is still far from easy over g-C3N4. Encouragingly, the surface strategies to modify g-C3N4 play an important role in tuning the surface properties resulted in improved performance. The summary, classification and mechanism understanding of surface strategies on g-C3N4 is of great significance. In this review, we firstly summarize the basic of photocatalytic water splitting. Then, three common strategies for improving the photocatalytic water splitting efficiency of g-C3N4 are classified in surface regulation, functionalization and assembly. As a focus, recent advances of surface strategies on g-C3N4 are discussed in detail combined with some previous studies, emphasizing the inner correlation between improved photocatalytic performance and corresponding surface strategy. Finally, a brief conclusion and the remaining challenges for artificial photosynthesis are presented. This review highlights the crucial role of the surface structure tailoring and provides ideas for designing highly efficient photocatalysts toward water splitting by surface strategies.