The invention belongs to the technical field of big data. The invention relates to a knowledge extraction and fusion method based on big data. Aiming at the problem that big data integration and knowledge extraction are greatly inconvenient due to the characteristics of timeliness, multi-source heterogeneity, weak relevance, isolation dispersity and the like of big data, the following scheme is provided: the method comprises the following steps of concept extraction, concept classification relation extraction, concept non-classification relation extraction, entity alignment and entity linking.According to the invention, for the obtained big data, an entity, relationship and attribute category system of each facet is constructed, syntax meaning analysis is carried out, candidate knowledgepoints are discovered, and then feature selection is conducted, so the knowledge of entity-relation-entity and entity-attribute-attribute value is automatically extracted from mass data, the completeness of big data acquisition is improved, the credibility and validity of the acquired data are improved, high availability, dynamic expansion and updating of a knowledge graph are supported, and effective fusion of big data is realized.