Hazards associated with roads, the home, work and play are highlighted in the artwork, which dates from between the 1930s and 1970s.
Head of Rospa Tom Mullarkey said the warnings are "still valid today".
A squirrel called Tufty Fluffytail is one of the characters featured.
Mr Mullarkey said: "We always knew that we had some poster artwork in storage, but it was only when we cleared our old warehouse that we discovered the sheer extent of our collection and the quality and age of the items.
"These posters would have carried simple yet important safety messages into homes and workplaces, helping people to prevent accidents to themselves, their loved ones and colleagues."
The posters were created by some of the foremost graphic designers of their time, including Cyril Kenneth Bird. Alternatively known as "Fougasse", he produced well-known wartime public information posters such as Careless Talk Costs Lives.
Conscientious squirrel Tufty Fluffytail, whose advice was often ignored by his disobedient friend Willy Weasel, even had his own road safety club - the Tufty Club - which in 1962 boasted more than 60,000 members.
Rospa president Lord McKenzie of Luton said: "Even in this information-saturated age of social media and 24-hour news, there is much that these now 'vintage' posters can tell us about the power of accident prevention.
"A little effort, a little forward planning and - above all - a little knowledge, can make a big difference in our quest to get the balance right between carelessness on the one hand, and risk-aversion on the other."
The book of posters, Safety First, by Dr Paul Rennie of Central St Martins College of Art and Design, is published on 18 June.
A collection of vintage safety posters found in a Birmingham warehouse are to be published in a book celebrating the centenary of the Royal Society for the Prevention of Accidents (Rospa).