Postal savings bank loans are invested in mobile banking, which means that when the Postal Savings Bank loans, it is necessary to write down the purpose and direction of the proposed loans on the mobile banking. According to relevant data, the loan investment refers to which departments, industries and enterprises of the national economy provide credit funds, which is directly related to support and restriction. The problem of delineating the loan scope should be clearly written when applying for a loan. Loan means that banks, credit cooperatives and other institutions issue loans to money-using units or individuals, and agree on interest and repayment date. Loans in a broad sense refer to loans, discounts, overdrafts and other borrowing funds. Banks put concentrated money and monetary funds out by means of loans, which can meet the needs of social expansion and reproduction for supplementary funds and promote economic development. At the same time, banks can also obtain loan interest income and increase their own accumulation.