Three types of 12-orifice mixing cruciform sampling probes, i.e. the sampling orifices with or without stub pipes and arranged in spiral form or on three radii, and one single orifice traversing probe were used to investigate the sampling representativeness in the measurement of gas turbine emissions. The results obtained in the experiment show that the distribution of carbon monoxide, CO, and smoke number, S.N., may have certain relations with the distribution of fuel and air in the combustor, and the three types of probes mentioned, the angular position of the cruciform probe and the manner of extracting sample off the mixing probe can make a deviation of less than 1 S.N. for smoke and about 5% for carbon monoxide.