Transformer noise from high voltage substation is an important low-frequencynoise source which can still cause higher subjective annoyance even if its A-weighted sound pressure leveli sl ow.I tb ecomes more and more difficult to further reduce its influence by conventional noise control technologies, so it is significant to finda newapproach to reduce subjective annoyance from transformer noise. Transformer noise sampled from a500 kV ultrahigh voltage substation wass elected as original noise samples. Pure tones, narrowb and pink noises and water sounds were added separately to original noise samples to adjust and control the transformer noise. Paired comparison test and letter cancellation test were used to compare subjective annoyance from noise and work efficiencyofsubjects exposed to noise before and after sound adjustment and control. Results showed that sound adjustment and control method of adding pure tones with frequencyo f1 01.5 Hz-120 Hz or narrowb and pink noise with the frequencyr ange of 100 Hz-200 Hz could not reduce the subjective annoyance of transformer noise. Interestingly,adding narrowband pink noise with the frequencyrange of 200 Hz-770 Hz and appropriate sound levelcould reduce the subjective annoyance of transformer noise, butitmight be due to the reason that the added narrowband pink noise sounded likethe sound of wind. Adding some kinds of water sounds, especially those with less low-frequencycomponent, could reduce the subjective annoyance of transformer noise. Results from letter cancellation test indicated that the relative performance quality score of subjects exposed to adjusted noise washigher than that of subjects exposed to original noise, butthe difference wasnot significant.