A total of 372,103 people have declared for Yes almost 16 months ahead of the referendum.
Chief executive Blair Jenkins said: "It was announced at the launch of the campaign on May 25 last year that the goal was to have one million signatories by Referendum Day, and today's figure is a significant milestone. At this stage of the campaign, these figures show that we are on course to reach our target."
Today, on the eve of the campaign's official first birthday, Mr Jenkins was joined by members of the Yes Scotland advisory board at The Fort shopping centre in Glasgow's east end, where they handed out information on why people should vote yes, and how.
Board member Sarah Jane Walls, who was brought up in a family that depended on welfare benefits and is now a successful businesswoman, said: "The UK Government's austerity measures are only just beginning to bite.
"But I fear the worst is yet to come. The only sure way to halt such inhuman policies such as the bedroom tax is to have control of our own affairs, get governments that we actually vote for and support policies that do not hurt the poorest and most vulnerable members of our society.'
The campaign also marked its first year in operation by announcing a nationwide "listening tour" in which Mr Jenkins and other members of the Yes Scotland team plan to visit every corner of the country to hear what kind of nation they believe Scotland should be.
Mr Jenkins said: "The primary purpose of the tour will be to engage with as many voters as possible, especially those who remain undecided, to give them the opportunity to ask the questions they believe have not yet been answered adequately, to voice any concerns they and their families may have about this life-changing vote and, quite simply, to make them feel part of the most important constitutional moment of theirs, their children's and grandchildren's lives."
He said Yes Scotland has recruited thousands of supporters, volunteers and ambassadors in what is claimed to be the largest community campaign in the country's history.
There are now more than 170 local Yes groups from the Northern Isles to the Scottish Borders and 15 sectoral groups such as Youth and Students, Trade Unionists for Yes, and Carers for Independence.
The support team have organised the distribution of more than three million leaflets, there have been more than 23,000 visitors to the Yes online store, and around 57,000 items of merchandise bought by supporters.