The Hall measurement equipment has been used to measure the mobility, the electron concentration and the resistivity of the 2DEG in the n-type modulation-doped GaAs/AlxGa1-xAs heterostruqture material before and during the sample being irradiated by FEL. Comparing the result of two cases, it is found that: 1) with enhancing temperature, the mobility decreases, and FEL makes the mobility increase; 2) the variety of the electron concentration with the temperature is more complex, but generally speaking, FEL makes electron concentration reduce; 3) with enhancing temperature, the resistivity increases, and FEL makes the resistivity decline, but the effect isn't obvious. These phenomena have all been analyzed in details.