Expenses reimbursement application method, mainly used in the accounting system of the enterprise resource planning (ERP) system. Wherein, for expense applicants, it provides an nullemployee expense application function setupnull in order to combine the inputs of general expense and petty cash applications, and the input operations are performed by the expense applicants; for petty cash keepers, it provides a nullpetty cash management function setupnull to allow the petty cash keepers to manage petty cash accounts; for accountants, it provides an nullexpense application and account establishment function setupnull, which allows the accountants to inquire the expense application data inputted by general employees and the petty cash keepers and reduces the input time of the accounting operations.