The failure of phased array antenna elements, can worsen the antenna performance such as absolute time delay. By use of the synthesis of array antennas and group delay theory，the variety of absolute time delay is analyzed, versus random distribution of elements failure and sub-array failure. By the random distribution numerical model, simulation results show that absolute time delay is affected by distribution and quantity of failure elements, and the deviation of time delay approaches to 0.39 ns on 20% elements failure. By the sub-array numerical model, the larger deviation of time delay will be caused by sub-array failure near the center of antenna array. The analysis results and the conclusion can be utilized to correct absolute time delay of phased array antenna.