Michael Conneeley had earlier been involved in trouble at the Raj Indian restaurant in Stamford which led to officers being called after a customer complained of being assaulted.
Allison Cunningham, prosecuting, told Lincoln Crown Court that Conneeley and his three friends had already left the restaurant by the time officers arrived but they traced him to a town centre pub.
Conneeley was arrested for a common assault at the restaurant but the court heard the 43-year-old resisted.
A male officer and Conneeley fell on to a Mercedes car parked in All Saints Road and during the incident PC Rose Brady was pushed onto the pavement.
The two men fell on top of her and she suffered a wrist injury that needed hospital treatment and kept her off work for two months.
Conneeley, formerly of Trinity Road, Stamford, but currently living at an undisclosed address in Glasgow, admitted assaulting PC Brady causing her actual bodily harm on August 26, 2007.
He also admitted assault with intent to resist arrest and threatening behaviour.
Conneeley was fined a total of £1,000 and ordered to pay £600 compensation, £700 prosecution costs and a £15 victim surcharge.
Judge Michael Heath told him: "Your behaviour in the restaurant that evening was disgraceful. It is an understatement to say that your behaviour did not get any better that evening."
Alex Dunn, defending, said that Conneeley did not deliberately injure PC Brady but what happened was due to his recklessness.