Radiative cooling as a spontaneous cooling phenomenon without any energy input has great research value and broad application prospects. However, environmental shields around the thermal emitter have a negative impact on the radiative cooling power of thermal emitters. A PTFE-Al was used as the radiative cooling thermal emitter, and the radiative cooling performances with different unilateral shielding angle were measured. The temperature difference of 7.4°C was achieved in an open and unobstructed environment, while the temperature difference of 2.8°C at the unilateral shielding angle of 90 deg. Furthermore, using the energy conservation model, we theoretically calculated the radiative cooling powers and the temperature differences of the thermal emitter under different shielding conditions, which were in good agreement with the experimental results.