Abstract: The main Jurassic source rocks of the Papuan Basin were systematically studied using the geochemical data of well samples and modern petroleum geological theory and hydrocarbon generation theory. The main Jurassic source rocks were divided into four formations, including the Magobu, Barikewa, Koi-Iange and Imburu formations from base to top, and the Maril Formation in the distal part. These source rocks were mainly distributed in the mid-west part of the basin. The Jurassic source rocks have abundant organic matter, with TOC contents mainly distributed between 0.5% and 2.0%. The TOC content of the Mid-Lower Jurassic is higher than that of the Upper Jurassic. The organic matter in the Jurassic mainly belongs to type Ⅱ₂-Ⅲ, mainly generating gas. The mature threshold in the Papuan Basin is 2 500 m. the Jurassic source rocks are in the low maturity to mature stage, with high maturity to over maturity in certain regions. This paper defined the lowest threshold of TOC content of 1.0% for effective Jurassic source rocks based on the relationship between TOC content and S₁ with the guidance of hydrocarbon generation theory. Combined with the distribution of organic matter abundance and maturity of the Jurassic source rocks, the predicted effective Jurassic source rocks are mainly distributed in the central Fly Platform and the restricted area of the Papuan Fold Belt.