Yingshan condensate gas field is the Mid-lower Ordovician Yingshan Formation reservoir in the north slope of Tazhong Uplift, Tarim Basin. It was discovered in 2006. The field reached 0.381 billion oil equivalent of proven reserves in place by the end of 2010. The gas reservoir consists Yingshan Formation excellent quasi-layered carbonate rock that is controlled by the fractured/caved reservoir-body with interbedded karstification. Gas is mostly distributed in the range of 0~200 m beneath the unconformity surface at the top of Yingshan Fm.. The Yingshan reservoir is directly capped unconformably with the Upper Ordovician Lianglitage dense argillaceous limestone. Hydrocarbon derived mostly from the Middle-Lower Cambrian dolostone and upper Ordovician carbonate rock and marlite. The exploration history, main geology characteristics, improving technique are reviewed on the marine carbonate gas field.