Accelerated Degradation Testing (ADT) is used to collect more performance degradation data under accelerated stress levels in a limited time. However, limited sample size or inadequate testing time may lead to the lack of degradation information, which causes inaccuracy of the evaluation of the lifetime. High Accelerated Life Test (HALT), High Accelerated Stress Screen (HASS) are common testing methods, whose information should be considered in evaluation of the lifetime and reliability. In this paper, Methodology for Integration of HALT, HASS and ADT (MIHHA) is proposed as the method with the multi-utilization of HALT, HASS and ADT. One difficulty of MIHHA is how to integrate the information of HALT, HASS and ADT to provide crucial information for product life prediction. We propose an evaluation method of MIHHA which integrated degradation information of HLAT, HASS into ADT evaluation based on Bayesian theory. This method would be a great help to the engineering application of MIHHA.