Peter Ralphs took the the money over two years to pay off massive credit card bills and store cards for items such as expensive clothes.
The charity in the county said the money represented more than five years of fundraising.
At Shrewsbury Crown Court today the 69-year-old, of Sutton Road, Shrewsbury, was told he would have to serve half of the three-year sentence and that proceeds of crime proceedings were under way to retrieve as much of the money as possible.
He had admitted at an earlier hearing fraud by abuse of power.
Judge Peter Barrie said that for two years Ralphs had helped himself to the funds of the Shropshire branch of the RSPCA , money that had come from legacies and donations by the public.
"The impact had a profound impact on the work that the charity could do and undermined the organisation's reputation," he said.
Elizabeth Power, prosecuting, said the fraud was uncovered in 2017 when an accountancy firm noticed that in 2015 the accounts had been said to have been examined by one of its retired accountants. In fact Ralphs had prepared the accounts and forged the signature.
The investigation that followed showed 30 transactions of money being paid out of the charity account to Ralphs and cash being withdrawn amounting to £184,001.
Miss Power said that Ralphs had been living beyond his means and said that the money had been used to pay off credit card bills.
Adrian Roberts, for Ralphs, said his client had never intended to defraud the charity.
He said Ralphs wanted to stress that neither his wife, nor the other trustees of the Shropshire branch of the RSPCA had had anything to do with the fraud.