The protesters broke the building's gate and entered the regional television facility as about 30 policemen stood idle nearby and did not intervene, Xinhua reported citing Interfax-Ukraine news agency.
Some 500 protesters gathered in front of the building, chanting slogans like "Russia!" and "Kiev cannot administer Donetsk!" and demanding the television station broadcast Russian TV programmes, instead of Ukrainian programmes.
Some people hoisted a flag of "the People's Republic of Donetsk" on the top of the building.
Earlier this month, pro-Russian protesters staged a rally to demand a referendum and some protesters complained that the television station did not give them a chance to speak.