The forward - the Blues' fourth Centurion after Steph Houghton,Jill Scott and Izzy Christiansen - joined the Blues in January 2016, having enjoyed a successful loan spell from her hometown Club Everton.
Her milestone was reached as City faced Atletico Madrid in the first Champions League match of the season.
Looking back on her time at the club, Parris has thanked boss Nick Cushing for moulding her into the player she is today.
“It’s been a journey to get to this point and Nick Cushing has played a passive part in helping me be that player.
“From the start, I joined as a very raw talent and he has moulded me into the winger I am today.
“I’m very proud to have made 100 City appearances – I’m so thankful to all of my team mates and the staff and hopefully there will be many more appearances to come.
“It doesn’t feel like 100 appearances at all! I couldn’t believe it, but every game has meant the most to me and it’s a special team and we can go far.”
City’s away encounter ended level with a goal a-piece after Gemma Bonner’s first half header was cancelled out by Kenti Robles’ last-minute strike.
Parris is confident City can finish the job when Atletico travel to Manchester in just a few weeks time.
“It was a tough away leg but sometimes you’re going to get these types of games.
“In previous years we’ve had quite an easy run up to the semi-finals but tonight shows what Champions League football is really about.
“We dug deep, we got stuck in and we got the away goal.
“When we get to Manchester we will score goals and Atletico will have to score even more so that away goal could be crucial.”