In order to resolve the carrier phase ambiguity in attitude determination, a new approach is proposed and discussed. A method for static baseline vector estimation is derivate based on the epoch-difference carrier phase and a receiver clock bias model. By using the estimated baseline vector, a float solution of ambiguity is computed. The range of potential integer ambiguity can be obtained with the error of estimated baseline. The implemented algorithm is tested with measurement data collected on static baselines. Experimental results indicate that, the integer ambiguity can be accurately determined after about 40 seconds with the present algorithm.