An international cooperative study of the Late Cretaceous biota and non-marine strata including the Cretaceous-Paleogene ( K--Pg) boundary in Jiayin near the Heilongjiang River，China during 2002-2010，is summarized in this paper． The strata includes the Upper Cretaceous Yong'ancun-，Taipinglinchang-，Yuliangzi-， and Furao formations，and the Paleocence Wuyun Formation consisting of Baoshantou Member and a Coalbearing Member． Seven palynological assemblages from Santonian to Paleocene are recognized，which is used for definition of the K--Pg boundary． Through the palynological analysis of three drilled boreholes ( XHY-2005， 2006，2008) in Xiaoheyan of western Jiayin，the K--Pg boundary is defined within 20. 00-20. 05 m in the borehole XHY-2006 ( as a standard boundary) which is just between the top of Furao Formation ( late Maasterichtian) and the base of Baishantou Member ( early Danian) ． These new research results are supported by paleomagnetic， geochemical and other analyses，also． On the other hand，the presence of eight taxa of Maasterichtian dinosaurs ( mostly hadrosaurids) have been recognized by the authors; and two mega-plant assemblages from the Yong'ancun Fm ( Santonian) to Taipinglinchang Fm ( Campanian) are confirmed． These research achievements indicate that the Upper Cretaceous-Paleocene in Jiayin can be well correlated to the strata in the neighboring Zeya-Bureja basin，Russia． The K--Pg boundary definited in Jiayin is the first well documented non-marine K--Pg boundary in China． Also the related paleoclimate，paleoenvironment and the mass extinctions in this area during the Cretaceous-Paleocene transition are also discussed．