To deal with the problem that Shanghai digital TV picture quality is poorer than traditional cable TV

picture qualities of several broadcasting taches are messured objectively. Lots of testing data are analyzed

and a conclusion is drawn that the encoding bandwith of encoders have great influnce on picture quality. Therefore

on the basis of current broadcasting system

a new method for increasing the encoding bandwith of encoders is discussed and put forward to improve the digital television picture quality.