With the advent of the big data era, in order to improve computational efficiency, Wang, et al.(2018) proposed an optimal subsampling algorithm for logistic regression, which provides a better tradeoff between estimation efficiency and computational efficiency. To solve the problem of multicollinearity among variables, this paper proposes an optimal subsampling algorithm in the context of ridge regression, and proves the consistency and asymptotic normality of the estimator from optimal subsampling algorithm. Numerical experiments are carried out on both simulated and real data to evaluate the proposed methods. Results show that the optimal subsampling algorithm produces similar results compared with the full data analysis, while significantly reducing the computational costs.