As a kind of coastal accumulation body in high-energy environment, natural gravel beach is a good coastal protection barrier due to its coarse particle size and large porosity. The gravel morphology is an important parameter to understand the gravel formation process, but it is difficult to obtain the quantitative parameters of a large number of gravels quickly and accurately. In this study, we surveyed three gravel beaches (Jiuzhangya, Yueyawan, Changtan) in the Beichangshan Island, four gravel beaches (Xianjingyuan, Linhai, Changshanwei and Mingzhuguangchang) in the Nanchangshan Island in the Shandong Province. We measured beach profile, collected gravel samples and took gravel images. Using the software ImageJ for digital image measurement in situ without interference, we can quickly obtain a large number of gravel morphologic parameters, including particle size, grinding roundness and shape ratio. The results show that the range of the particle size is 4−79 mm, which was mainly pebbles. The average particle size of the beach in the Beichangshan Island is slightly smaller than that in the Nanchangshan Island, with the largest average particle size of gravels in the Jiuzhangya Beach of the Beichangshan Island and the smallest one in the Xianjingyuan Beach of the Nanchangshan Island. From beach berm to the high tidal line, the average particle size decreases gradually, but increases at waterline. The range of roundness of gravel is 0.59–0.75, and the grade is round. The gravel beaches have reached a relatively mature stage based on roundness, with the best roundness in the Yueyawan Beach and the worst roundness in the Changtan Beach of the Beichangshan Island. The gravel roundness increases from land to sea. The shape ratio ranges from 1.36 to 1.77, which is negatively correlated with the gravel roundness (R²=0.98). The gravel gradually changed from long strip to elliptic shape from land to sea. The gravel beaches morphology of the Changshan Island is affected by the provenances, dynamic conditions and human activities. The slope range of the gravel beach in the study area is 16%−35%, and they are positively correlated with the gravel particle size.