Imran now has 15 days to appeal against the verdict.
Talking to Dawn, the prosecutor general (PG) had said all the requisites of justice and fairness had been strictly observed during the trial proceedings.
The court will announce the verdict in his presence. The trial was conducted in the prison for security reasons.
Zainab's parents are not alone in their desire as last month, the Chief Minister Punjab Shahbaz Sharif also echoed the same, saying if it was possible, he would have preferred to carry out execution of Imran Ali in public to make an example and deterrent to halt such criminalities in the future.
On February 12, the judge asked Imran whether he accepts the charges, but he pleaded not guilty, after which the court indicted him in the case and started regular proceedings.
The girl's family registered a complaint with the local police after she went missing on January 4.
On January 9, a police constable recovered her body from a heap of rubbish.
Shoot female rebels in the vagina - Rodrigo Duterte
De Jesus said the president "further confirms himself as the most unsafe macho-fascist in the government right now". Duterte responded by saying he was okay with imprisonment as long as conjugal visits by many women were possible.
Law enforcement agencies came under mounting pressure to find the killer of Zainab and other children in the region. During the search, DNA test was conducted on more 1,100 people living in the vicinity.
The massive search led to the arrest of Ali, whose DNA sample matched those found on eight victims, including the seven-year-old girl.
Earlier, his lawyer had withdrawn from the case after Ali had confessed to the crime, it was reported. He also admitted to murdering five minor girls at an under-construction site and throwing away the bodies of three others in a garbage pile, the report said quoting sources.
Muhammad Amin, father of Kasur's seven-year-old Zainab, has demanded that the prime suspect in the rape and murder case of his daughter should be stoned to death.
The murder of 7-year-old Zainab Ansari sparked riots across Pakistan, with hundreds of people protesting against police negligence.
A number of children have gone missing in the Kasur district since 2015, when police say they uncovered a pedophile ring tied to a prominent local family.
At least 10 such cases a day of child abuse are reported in Pakistan, according to Sahil, a non-governmental organisation that works on child protection.