With the increasing demand for financial data security and sharing efficiency, the security sharing strategy of financial data based on homomorphic encryption technology has been widely concerned. This paper proposes a financial data security sharing model based on the Paillier algorithm, which includes a data layer, an encryption layer, a sharing layer, and an application layer. The model uses the Paillier algorithm to obtain a homomorphism when increasing the amount of encrypted financial data, so as to realize the safe sharing of financial data through additive homomorphism. The experimental results show that compared with RSA and Elgamal algorithms, the Paillier algorithm has great advantages in ciphertext length, error rate, and calculation efficiency, and the error rate is as low as 0.6%, which proves its effectiveness and reliability in financial data security sharing.