Abstract: Entity relation extraction is an important task in information extraction which helps people find knowledge quickly and accurately in various text. Traditionally, entity relation extraction methods require a pre-defined set of relation types and a corpus with manual tags. But it is difficult to build a well-defined architecture of the relation types and it takes a lot of time to label a corpus. Open entity relation extraction is the task of extracting relation triples from natural language text without pre-defined relation types. There is a lot of research in the field of English open entity relation extraction, but rarely in the field of Chinese open entity relation extraction. This paper presents the UnCORE (unsupervised Chinese open entity relation extraction method for the Web). UnCORE is an unsupervised open entity relation extraction method which discovers relation triples from large-scale Web text. UnCORE exploits using word distance and entity distance constraints to generate candidate relation triples from the raw corpus, and then adopts global ranking and domain ranking methods to discover relation words from the candidate relation triples. Finally UnCORE filters candidate relation triples by using the extracted relation words and some sentence rules. Results show that UnCORE extracts large scale relation triples at precision higher than 80%.