We propose a high-dynamic optical angiography(HDOA) method to obtain blood flow images of a small biological specimen in vivo. High dynamic range exposure time is set to achieve high-dynamic integrated time modulation, which involves dynamic integrated effect and absorption effect. With this method, each-level vessels can be imaged with similar clarity. Moreover, the vessels in locations with different thickness and absorption coefficient can be reconstructed in the same image. Experiments on phantom and in vivo Gold Pristella Tetra were performed to demonstrate that HDOA can achieve each-level vessels imaging based on dynamic integrated effect and absorption effect.