The AMSAA model is the most widely used model, applicable for reliability growth track. However, there exist some problems in its application. Based on summarized AMSAA growth model, the paper puts forward an improvement on the model, deduces new expressions to forecast reliability growth test time for a specific MTBF value by Newton iteration, and programs software by this method to evaluate reliability growth. The new solution could dynamically estimate and predict the reliability of equipment, track and forecast the equipment reliability growth. It is more exact than the usual measurement, and the calculation of the software is fast and precise.