Crown prosecutor Nicole Copeland said Xia had expressed excitement about her age.
Copeland said it was serious premeditated offending and not spontaneous sexual activity.
In conversation, rules were established for when they would meet, as Xia warned the girl not to tell police, the court heard.
On the first occasion, the 13-year-old had walked to the back of her school before Xia drove her to an underground carpark.
There, multiple sexual acts occurred and later that month similar offending happened again in the same secluded carpark.
When police conducted a search warrant on June 6, they seized objectionable material that was in Xia's possession from which they selected 17 images for prosecution.
Later, police searched his shared Google account and found he had accessed it after his arrest to permanently delete some items, the court heard.
Defence lawyer Ian Brookie said Xia was the "architect of his own misfortune" and the defence case did not dispute he was at fault.
Brookie said there were a number of things that needed to be taken into account during sentencing including his fall from grace and that his employment would be forfeited.
Xia had no prior convictions in New Zealand or in China and was eligible for a 25 per cent discount for pleading guilty.
Brookie said while it was not certain when Immigration New Zealand would act, it was effectively a no-brainer that he would be deported.
Xia had sought help from a clinical psychologist, including undertaking 12 therapy sessions with someone who had a specialty in helping child sex offenders.
The 41-year-old had also voluntarily offered $10,000 in reparations to the victim's family.
Judge Eddie Paul said the victim's parents had made several disturbing observations about the change they had seen in their daughter - including that she no longer smiled often.
"Certainly for her parents, their world has collapsed," he said, adding the mother could not stop crying.
Judge Paul said it was premeditated offending that had caused ongoing psychological harm to the victim.
He took into account the submissions made by the defence, including that the clinical psychologist's current assessment was that Xia posed a low risk.
With that in mind, the judge, who also has experience as a convenor for the Parole Board, said it was unlikely he would get treatment in prison as he could not jump to the front of the queue.
Deportation was also a "significant" consequence that would follow Xia's conviction.
Judge Paul sentenced Xia to a year of home detention on the charges, that would be served concurrently, and post-detention conditions would apply for the maximum period.
The Auckland District Court judge said reparations of $10,000 must be paid immediately.
He also issued a first strike warning but did not place Xia on the Child Sex Offender register. Doing the latter is up to the judge's discretion when an offender is not going to serve a term of imprisonment.
