The invention discloses a fund financing method and device based on a SDK. The method comprises steps that a first application receives a transaction request via an interface provided by a second application and executes financing product transaction operation in a first application account, wherein the interface is established by the second application according to the software development kit SDK of the first application; after the financing product transaction operation is completed, an encrypted account password for paying the financing product transaction operation in a second application account is obtained; and the account password is sent to the second application to enable the second application to verify the correctness of the account password, when the second application determines the account password is correct, the second application executes fund payment operation. The invention achieves combination of the internet finance capability and the mobile internet marketing capability of the bank with the regional operation capacity of small and medium-sized commercial banks, reduces the service cost of inclusive finance, enables the small and medium-sized commercial banks to have the internet finance service capability, and provides better finance services.