Glass substrate with novel compact hemisphere pits surface structure is studied. Based on rigorous coupled wave analysis (RCWA), the diffraction of the structured glass substrate is thematically calculated. It is found that this kind of glass substrate can effectively diffract the normal incident light. It has high haze when the period is around 2.6 μm with long wavelengths of 0.6~0.8 μm. This glass substrate is utilized in thin film solar cells for light trapping in our simulation. Compared with flat thin film structure, the average absorption is enhanced by 18.7% within 0.3~0.8 μm and the absorption is enhanced by 17.9%~77.7% within 0.6~0.8 μm bandwidth for the structure with a period of 2.6 μm under normal illumination.