Abstract: Characteristics of solid argon and 4∶1 methanol-ethanol mixture were systematically studied by using ruby fluorescence technique under high pressure and low temperature (77 K) in the gasket diamond anvil cells. The pressure distribution was determined by measuring the special shifts of the R1 line of ruby at different positions within the sample chamber. Experimental results showed that the values of |p/p| and p/p which reflect the degree of inhomogeneity in solid argon medium are less than 3% and 2% in the pressure range from 0 to 16 GPa, respectively. Under high pressure, the shape of ruby R lines is similar to that at ambient pressure except for broadening with increasing pressure, which indicates solid argon is an excellent pressure-transmitting medium under high pressure and low temperature. On the other hand, the values of |p/p| and p/p are larger than 3% and 2% in 4∶1 methanol-ethanol mixture, respectively, except for the initial pressure. Moreover, the shaper of ruby R lines at different positions are also different under higher mean pressures. These results indicate the methanol-ethanol mixture can not be used as a good pressure-transmitting medium under high pressure and low temperature.