The output characteristics of GaAs cell are keys for the laser wireless power transmission system design. The measurement platform for the output characteristics of GaAs cell is established by single-junction GaAs cell and 1064 nm fiber laser. The influence rules of laser power and temperature on the short-circuit current, open-circuit voltage, peak power, fill factor, and conversion efficiency are measured. The measurement results show that the conversion efficiency firstly increases and then decreases with an increase in laser power, and reaches a maximum of 54.5% at the laser power of 0.405 W, whereas the conversion efficiency decreases with an increase in temperature, and decreases slowly with an increase in laser power.