Adam Teese, 26, was accused of 'throwing a missile on to the pitch' during the Manchester derby in January.
Bellamy, playing for City in that match but currently on loan to Cardiff, fell to the ground after he was struck by a coin in the 50th minute as he went to take a corner during the Carling Cup semi-final at Old Trafford.
Downed: Bellamy reacts after being struck by a coin during the Manchester derby
Unemployed Teese, who lives with his parents in Nelstrop Road North, Heaton Chapel, Greater Manchester, was due to go on trial at Trafford Magistrates' Court.
But the prosecution's key witness, steward Ashley Orr, could not be contacted by the court and the case was thrown out.
Teese's mother, Deborah, 49, sat next to her son throughout the game and was due to be called as a witness for the defence.
Sore point: Bellamy goes down in front of the United supporters
The family had to change their phone number after receiving abusive phone calls from City fans and numerous unwanted takeaways, she said.
'We are happy and relieved but had it gone ahead we could have proved he was innocent,' she said.
Teese, who has always protested his innocence, said he was scared to go out in case he was attacked by a City fan.
'I am going to move on with my life now,' he said.
Spain are to blame for Silva's slow start, says Man City boss ManciniMan United fan denies throwing coin that struck Bellamy in Carling Cup semiGiven will not be handed Europa League chance by City boss ManciniMan United promise to ban fans found guilty of throwing missiles at BellamyMANCHESTER CITY FC