The invention discloses a business application construction device and method based on a cloud environment. The business application construction device comprises a project configuration tool, a bind lessee configuration tool, a multi-data source configuration tool and a project construction tool which are arranged in the cloud environment, wherein the project configuration tool is used for creating N projects, and N is a positive integer; the bind lessee configuration tool is used for creating N lessees and performing one-to-one binding on the N lessees and the N projects; the multi-data source configuration tool is used for creating N groups of business data sources and performing one-to-one binding on the N groups of business data sources and the N projects; the project construction tool is used for utilizing the corresponding business data sources to perform business application construction after the lessees log in the corresponding projects according to limits of authority. The business application construction device and method greatly improve the development efficiency, and are short in development time and low in maintenance cost and acquisition cost; in addition, as the multi-database and multi-data source technology is adopted, data security and confidentiality of all business systems are guaranteed.