Several liquid oil seeps were discovered recently in the central Qiangtang block. Biomarker parameters indicate that crude oil of the seeps and the Beileico- Andarco Petroliferous Sequence (BAPS) are both derived from the Early Jurassic Toarcian oil shale. The Lower Jurassic oil shale characterized by high content of TOC, large potential of hydrocarbon generation and lower maturity of organic matter is the main source rock and major oil generating strata in the Qiangtang basin. Seismic reflection profile and drilling logs reveal that the Toarcian oil shale as thick as 110~150m covers all over the Northern Qiangtang Depression (NQD). Depth of the Toarcian oil shale ranges from 4500~3000m in most areas of the NQD to 3000~1000m in both wings of the Baodaohu anticline. Early Cenozoic thrust and deformation caused uplift of the Toarcian oil shale, which forms oil shale outcrops in the Bilog Co, Shenglihe, Changsheshan and Tuonamu Zangbu, and the Toarcian oil shale rise to as deep as 522~675m at core summit of the Bandaohu anticline. Methods of chloroform bitumen “A” and hydrocarbon generation rate of Toarcian oil shale sampled from different areas were taken for evaluation of oil resource in the focused region of NQD. It is estimated that the crude oil as much as 5000~10000 million tons occurs in the Bandaohu- Donghu area as large as 20000km2 after first time hydrocarbon generation of the Toarcian oil shale, and second time hydrocarbon generation of the oil shale forms 2440 million dons crude oil in the Cenozoic. The NQD contains mega volume of crude oil after two times hydrocarbon generation and is of prospective for oil exploration in the Qiangtang basin.