Abstract: The PCS software of long-distance oil and gas pipeline SCADA system is developed on the basis of the commercial database Oracle. In order to guarantee its support on the open source database PostgreSQL and realize the optimization of PostgreSQL, the functions and syntax structures of Oracle and PostgreSQL databases were analyzed in detail in this paper. Then, it was proposed to replace the Oracle table partition function by using the table inheritance method of PostgreSQL. The stored procedure in PCS was modified and optimized by analyzing the syntax difference of stored procedure between Oracle and PostgreSQL. The direct reading of local files by the stored procedure was realized based on the extended support of PostgreSQL for Python language. The synonym function of Oracle was replaced by creating new views in PostgreSQL. The directory object function of Oracle was replaced by creating an object data table in PostgreSQL. A software architecture method was proposed to realize the support of PCS software for Oracle and PostgreSQL databases. Based on these modifications, the support of PCS for PostgreSQL database is successfully realized and the performance of PostgreSQL database is optimized.