Aerodynamic force and moment measurement is a very difficult problem to solve in the hypersonic research area. Traditional hypersonic wind tunnels usually produce flows with low total temperature, and therefore, the thermo-chemical reaction, one of the key mechanisms in hypersonic flows is ignored[1]. High-enthalpy shock tunnels are capable of generating high-temperature flows but its effective test-duration is too short to do the force and moment measurement. Moreover, for most of the hypersonic experiments, there is no available scaling criterion as that in low speed test, which makes the aerodynamic force and moment measurement even more difficult[2]. Under the support of National Major Project of Scientific Instrumentation R&D, a big shock tunnel, named under the serial number in LHD laboratory, was developed based on the backward-running detonation driver. Its performance tests demonstrated that the facility is capable of reproducing the pure airflow with Mach numbers from 5 ~ 9 at altitude of 25 ~ 50 km[3]. By big, it includes both nozzle size that can accommodate large scale modes and the facility length that promotes more than 100 ms effective test-duration. Taking advantage of the JF12 shock tunnel, the research on aerodynamic force measurements was carried out with a homemade six components stress balance. The test model is a sharp cone with 100 angle, and measured 1500 mm in length and 57 kg in weight. The test condition is for Mach number of 7 with the total temperature of 2200 K. Some of the experimental data collected at a 50 attack angle are presented in Fig.1. These voltage signals indicated that low frequency oscillations are observable from the pitching moment, but there are at least three periodical signals obtained within the 100ms test duration. It means that the high accuracy could be reached with the stress balance signals. The further experimental data demonstrated that the force and moment accuracy of the JF12 shock tunnel is in good agreement with blow-down wind tunnels if the real gas effect is not obvious in test cases. When the nose shock of the test modes becomes strong enough to excite gas vibrations, the significant difference is observed from high Mach numbers and high attack angles. This is the real gas effect has been demonstrated for long time from flight tests.