Wudalianchi Lake (48°40’N~48°47’N,126°06’E~126°15’E) is located in Wudalianchi City, Heilongjiang Province, China. Combined with the sediment age,environmental changes of Wudalianchi Lake were reconstructed. The results showed that the environmental history could be divided into four stages as follows: 1920s~1950s,median diameter of sediments was large, TN and LOI550℃ showed increased trends, Al and Fe contents of core sediment also increased, which indicats that lake environmental changes were possibly related with human activity such as land reclamation. 1950s~1980s,human activity (such as deforestation,destruction of grassland) became the main influences which led to TN, Al and Fe contents to increase. However,median diameter was small. 1980s~2000s, total nitrogen and phosphorus increased more rapidly, heavy metals also showed an increase trend, which could be attributed to extensive use of fertilizers, pesticides,phosphorus-containing items, leaded gasoline, and development of industry. Since 2000s, eutrophication has been the most important problem due to extensive input of nutrient loads to Wudalianchi Lake.