Some definitions about oil from coal measures as oil-prone source rocks and problems of mac-erals related to oil generation and the threshold, range and peak of oil generation are reviewed. This paper suggests that the oil genetic potential of mudstone is higher than that of coal measures through comparing the characteristics of the macerals composition and evolution and maturity of soluble organic matter with the maturity of crude oil and abundance of organic matter, the thicknesses of coal measures and quantity of soluble bitumen in coals with those of mudstone and soluble bitumen of coal and its evolution with soluble bitumen of crude oil from coal in coal-bearing basins in the Jurassic System of China.