The 33-year old man used “a metal tool” to break into the room at the First Hotel Kong Frederik in Copenhagen before leaving with the safe, Copenhagen police confirmed to AFP.
At a custody hearing the man said he was “very ashamed” of what he did and that he had not been aware of who was staying in the room.
Pleading guilty, he argued that there had been 1,900 kroner (255 euros, $277) less in cash than stated in the indictment.
The man was arrested in the southern port of Rodbyhavn as he prepared to board a ferry to Germany.
Liu was in Denmark to work with Danish shoe brand Ecco, for which she does promotional work in China.
The jewellery and watches “were not something she used in our photo shoot”, an Ecco spokeswoman told AFP.
“She is very well known and has a broad following on social media,” she added.
Liu wrote about the incident on the Chinese social media network Weibo, posting on December 8: “Although terrified for 24 hours… I still love this fairy-tale country.”
She thanked Danish police, as well as the Chinese embassy in Denmark and the Danish embassy in Beijing.
“Thanks and greetings to all friends, everything is going well with me, and I will leave soon.”