The printing resolution and scale of projection-based 3D printing are affected by the pixel size and projected light power. An effective and versatile method to print complex constructs with high resolution and large area is still required since light distribution in printing systems is generally non-uniform. Here, we propose a projection-based continuous 3D printing with the grayscale display method to serve as an effective and precise way to improve printing resolution and area. The light characterization results demonstrated that the power density presented a non-uniform distribution, and the power values are linear to the excitation power. After modifying the masks into grayscale according to the duty cycle of the digital micro-mirror device (DMD) display, projected light exhibited improved uniformity along with expected light power and uniform ratio. To validate this developed printing process, the grayscale continuous printing of mesh and hexahedron frame constructs enabled a remarkable increase in the printing area and alleviation of under/over curing. This work reveals significant progress in printing of constructs at larger area and higher resolution in projection-based continuous 3D printing under non-uniform light.