Abstract: This paper presents a methodology to accurately predict link error performance based on capacity equivalence for a wide variety of channels. A metric based on Shannons channel capacity is introduced and combined with a new penalty factor Q relating to channel fading rate. And a new segment equivalent method is also presented to make use of the information of each slot in the prediction. This method requires a Q look-up formula and a reference AWGN performance curve per channel code rate and modulation. Simulation results show that this method provides a good prediction performance for different fading rate channels. Here is an example of Turbo code performance prediction, it is convenient to apply to other link-level cases.