| Numbers of dinosaur egg fossils, espically famous “Baby Louie” dinosaur egg embryo fossil, kept in the Gaogou Formation in the Upper Cretaceous Series in the Xixia of Nanyang Basin, Henan province. After researching the section embedding egg fossils in this paper, palaeoclimate and palaeoenvironment had been constructed and the paleoenvironmental background and reason about dinosaur extinction in the Cretaceous had understood in further. A 267.8m section had been determined in the Zhaoying village made up of Upper Cretaceous Gaogou Formation over Devonian Nanwan Formation. After bulk sediment elements, carbon and oxygen isotopes analyzed, sediments in the Gaogou Formation mainly came from the magmatic rocks from the Xionger Mountain. Dinosaur egg fossils embedding in situ kept in the flood plain belt of the foot of mountain to the far plain range of 200 to 800m asl. Runoff in the river and surface came from rain. River and flood plain sediment environments changed quickly with the precipitation changing so that dinosaurs came and went between foot of mountain and flood plain. Under the warm and wet condition, higher runoff formed the flood plain sediment environment with muddy silt rocks, which was a fitting for the dinosaur living and egging and hatching. When the precipitation rising, flood plain environment changed to the river environment to make dinosaur migration. From the saved completely dinosaur egg fossil and the proxies significance, river hydrodynamic was not very strong and ascended slowly. Organic matter in the strata including dinosaur egg fossils came from germ, alga, and aquatic and terrestrial plants, but was poor vegetation by biomarker analysis. Based on the geochemical proxies Si/Al, CIA, Rb/Sr, and carbon and oxygen isotopes of carbonates, paleoclimate during the Gaogou Formation changed quickly as warm/dry-warm/wet-dry-warm/wet-dry process, and had a dry tendency. Under the dry condition, precipitation and effective humidity decreased, runoff decreased also with vegetation cover rare so that huge animals could not find enough food for living. Based on the researched to the dinosaur egg embedding and paleoclimatical reconstruction during the late Cretaceous in the Zhaoying village of Xixia county, Henan province, the main factors to make dinosaur extinct gradually were the palaeoclimatical and paleoenvironmental deteriorate to make numbers of dinosaur eggs hatched incompletely and vegetable decreased largely.