In this letter, we reported a high-resolution photoacoustic microscopy (PAM) to image erythrocytes and blood vessels. The developed system had the ability to provide a lateral resolution of 1.0 μm at the wavelength of 532 nm with a × 10 objective. First, we used a sharp edge to measure the lateral resolution of the PAM and testified the stability with carbon fibers. Then, using this system, in vivo blood vessels and capillaries of a mouse ear, even a single erythrocyte can be clearly imaged. There was a pair of accompanying venule and arteriole, whose detailed and further complicated branches can be clearly identified. And likely red blood cells (RBCs) arrayed one by one in microvasculature was also shown. The experimental results demonstrate that the high-resolution PAM has potential clinical applications for imaging of erythrocytes and blood vessels.