As a type of data with both temporal and spatial dimensions， spatio?temporal data is widely used in supply chain management， e?commerce and other fields， which integrity and security are of great importance in practical applications. Aiming at the problems of lack of transparency and easily being tampered of data in the current centralized storage of spatial?temporal datasets， a blockchain construction and query method for spatio?temporal data was proposed by combining the decentralized， tamper?proof and traceable characteristics of blockchain technology with spatio?temporal data management. Firstly， an improved Directed Asycline Graph Blockchain （Block?DAG） based blockchain architecture for spatio?temporal data， namely ST_Block?DAG （Spatio?Temporal Block?DAG）， was proposed. Secondly， to improve the efficiency of spatio?temporal data storage and query， a storage structure based on quadtree and single linked list was adopted to store spatio?temporal data in the ST_Block?DAG blockchain. Finally， a variety of spatio?temporal data query algorithms were implemented on the basis of the storage structure of ST_Block?DAG， such as single?value query and range query. Experimental results show that compared with STBitcoin （Spatio?Temporal Bitcoin）， Block?DAG and STEth （Spatio?Temporal Ethereum）， ST_Block?DAG has the spatio?temporal data processing efficiency improved by more than 70% and the comprehensive query performance of spatio?temporal data improved by more than 60%. The proposed method can realize fast storage and query of spatio?temporal data， and can effectively support the management of spatio?temporal data.