The League 2 club lauched the scheme on Tuesday and they have been asked to choose from three designs made by their kit supplier Sondico.
Club spokesman Colin Farmery told the club’s website: “All three designs have their respective merits and it will be interesting to see what fans prefer.
“The club has worn yellow in the late 80s and the late 90s and we have had black alternative kits on a number of occasions. The purple option is the more radical departure.”
Fans have till April 7th to vote in the online poll.
Portsmouth join the likes of AFC Wimbledon, QPR and Plymouth Argyle in allowing their fans to vote for their choice of kit.