In liquid rocket engine turbopump, it is difficult to evaluate turbine performance for high pressure, high temperature circumstance. Turbine test is often done by using air at similarity condition so that the turbine can be tested at lower risk. This paper describes an air similarity test program of liquid rocket engine turbopump turbine. A test facility has been built to evaluate aerodynamic performance of turbines. The test facility consists of high pressure air supply system, mass flow rate measuring nozzle, test section, hydraulic break, exit orifice for pressure control, instrumentation and control system. This paper also presents how to decide the similarity conditions of the turbine test and describes how to control test conditions. Relative standard deviation of measurement parameter was less than 1% and measured turbine efficiency corresponded with analysis result within 2%.