Tomasz Kocik, 38, was described as an "obsessively jealous, controlling boyfriend", who behaved violently towards Marta Ligman, 23.
He was caught on CCTV pulling the suitcase and her body was found in the water in west London.
Post-mortem tests showed she died from hypothermia after suffering a beating.
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Kocik, of Buckingham Road, Harlesden, north-west London, had admitted dumping the body but denied murder, claiming she died following a drug-fuelled sex session.
The court heard the suitcase was seen floating in the canal near Maida Vale and a post-mortem examination revealed Ms Ligman, who was just 5' 2" tall, had extensive bruising over her body and multiple fractures to her ribs.
There was no evidence she had drowned.
Prosecutor Timothy Cray told the Old Bailey: "If the initial attack had not killed her outright, the fact that she was then zipped into a suitcase and left inside would also have proved fatal because of the effects of being left in such a constricted space.
"He attacked Marta, put her in a suitcase and when she was dead or dying, he put that suitcase in the Grand Union Canal.
"These are the acts of a man intent on covering up a dreadful crime."
Polish national Kocik only reported Ms Ligman as missing after her body was discovered and the story about a woman being found dead in a suitcase was "all over the news," the court heard.
He initially told Ms Ligman's relatives he thought she had gone to Poland and he had not tried to find her in order to give her some space.
Kocik is due to be sentenced on 27 November.
A man who put his girlfriend's body in a suitcase and then dumped it in the Grand Union Canal has been found guilty of murder.