The human rights campaigner had been hoping to lodge an appeal after a protection order against China's former Brisbane consul-general Xu Jie was dismissed in August 2020.
He had been seeking a Peace and Good Behaviour Act (PGBA) application, claiming Dr Xu started a brutal, systematic harassment campaign against him.
After Mr Pavlou was assaulted at a July 2019 protest at University of Queensland, Dr Xu issued a press release as Brisbane consul-general which the activist said incited violence against him.
His PGBA application was unsuccessful three years ago after a Brisbane magistrate ruled Dr Xu had consular immunity.
Mr Pavlou lodged the appeal in August 2022 after seeking legal advice from international experts even though Dr Xu is no longer Brisbane consul-general or in Australia.
However, it was nearly two years after the time limit expiry to appeal the order.
Mr Pavlou needed an extension of time to appeal, but that was refused by Brisbane District Court Judge Bernard Porter on Monday.
Judge Porter said a PGBA order would be "unnecessary and futile", with Dr Xu out of the country and no evidence of any alleged conduct since July 2019.
Dr Xu left Australia in March 2022 and is now a Chinese ambassador to the Cape Verde Islands.
"I think it is fair to assume that the respondent (Dr Xu) no longer has any duty nor interest in involving himself in events in Queensland," Judge Porter said in his judgment.
Mr Pavlou was not present in Brisbane on Monday, but had described it as a "landmark case" at a November hearing.
"It's the principle. I think the court should issue an order against him (Dr Xu) to make clear such conduct is unacceptable ... even if Xu Jie has left the country," Mr Pavlou told AAP.
"His statement ... that really did act as the starting gun to the extended and at times brutal campaign of harassment me and my family have received in Australia."
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