The Police Investigations and Review Commissioner (Pirc) said the 28-year-old man was not posing an imminent threat when the Specially Trained Officer (STO) fired on him in Bannockburn, Stirling in September last year.
The watchdog recommended that the officer undergoes refresher training and reassessment in the use of the Taser.
Police Scotland last year equipped 500 officers with Tasers amid concerns over unarmed officers being sent to violent incidents.
The Pirc said that during the incident, the man had become aggressive towards the officers and had challenged them to a fight.
He was charged with a number of offences and later convicted.
Calum Steele, general secretary of the Scottish Police Federation, said: “It is surprising that the Pirc makes no comment on what the officers should have done, rather they criticised what
"Clearly the Pirc would have preferred officers physically tackled this individual where a violent struggle (and risk of serious injury) was the inevitable outcome.
"I want to place on record the appreciation of the SPF to the officers who resolved this incident without anyone involved being injured. They are a credit to the communities they serve.”