Accurate yield estimation is one of the important yet challenging tasks for both pre-silicon verification and post-silicon validation. In this paper, we propose a novel method of Bayesian model fusion on Bernoulli distribution (BMF-BD) for efficient yield estimation at the late stage by borrowing the prior knowledge from an early stage. BMF-BD is particularly developed to handle the cases where the pre-silicon simulation and/or post-silicon measurement results are binary: either "pass" or "fail". The key idea is to model the binary simulation/measurement outcome as a Bernoulli distribution and then encode the prior knowledge as a Beta distribution based on the theory of conjugate prior. As such, the late-stage yield can be accurately estimated through Bayesian inference with very few late-stage samples. Several circuit examples demonstrate that BMF-BD achieves up to 10× cost reduction over the conventional estimator without surrendering any accuracy.