Isle of Wight born former Oxford United and Yeovil Town defender Martin, 28, started his pro career at Southampton in 2009 after playing for non-League Eastleigh.
Martin joins City after leaving Oxford United.
New City boss Taylor said: "Aaron is a player with a lot of experience playing at a higher level. He is a good age and is highly motivated to drive the team on to the next level.
"He is a strong, tall, ball playing centre half and it is important that we have a lot of options defensively. I'll be looking to boost our defensive ranks further over the next few weeks.
“The player’s attitude and character are important. I want to bring in good players and good characters.”
• Experienced former Notts County striker Jonathan Forte, 31, has become Taylor's second summer signing at Exeter City.
Forte was a play-off semi finalist with County last term, scoring 10 times.
He said: "I’ve been around for a bit, so I know my way around League One, Two and slightly higher, so it stands me in good stead."
