Saturday's decision was the third adverse ruling against the embattled former prime minister this week and comes before national elections on Thursday that he is barred from contesting.
The jailed Khan, 71, has in recent days been sentenced to 10 years for leaking state secrets and 14 years along with this wife for illegally selling state gifts.
"After hours of rushed hearings at court, no cross examination of witnesses, and no due process - a mockery of the law," Khan's party, Pakistan Tehreek-e-Insaf (PTI), said in a statement.
"With the way these trials are being conducted, there will be a huge question mark on the February 8th elections. This is a test case for Pakistan's higher judiciary."
The two were each fined 500,000 rupees ($A2700), ARY News reported.
Bushra was accused of not completing the waiting period mandated by Islam, called "Iddat", after divorcing her previous husband and marrying Khan.
The Khans signed their marriage contract, called a "Nikkah", in January 2018 in a secret ceremony seven months before the charismatic former cricket superstar became prime minister for the first time.
There was controversy over whether they had wed before the period was complete.
After initial denials of the January marriage, PTI confirmed it weeks later.
The Khans both denied any wrongdoing.
Khan is in prison in the garrison city of Rawalpindi, while his wife had been allowed to serve her sentence at their hilltop mansion in Islamabad.
He already faces a 10-year disqualification from holding public office.
It was not immediately clear if the sentences would run concurrently or sequentially.
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