In the invention, the sending party sets up buffer area, and fills data as 
data source of 
simulation file; and the receiving party creates buffer area to receive data. After test is started, the method executes steps: specifying remote 
server file (RSF), or determining 
route, name and size of RSF; calculating transmission positions of starting and stopping each thread; creating prearranged number of transmission thread, and starting up execution of transmission; obtaining size of transmitted data (TD) and 
transmission time (TT) of each thread, making statistics for 
throughput; when TD reach specified size, or TT reaches specified time, or user stops testing, the method stops each transmission thread. Making the most of network capacity, the invention eliminates unnecessary interference from reading / writing files so as to reflect actual 
throughput of network precisely and raise reliability. Moreover, 
automation control increases easy to use the test device and efficiency of test.