Through constructing a double optical feedback semiconductor laser chaotic system, the time delay signatures of chaos are investigated experimentally under different working conditions. The results show that, time delay signatures of chaotic output can be suppressed efficiently through adjusting the feedback strength of one cavity carefully and fixing the feedback strength of another cavity. Meantime, there is a big time shift which is the deviation between extracted delay time and real system delay time. Therefore, double optical feedback semiconductor laser chaotic system can efficiently hide the delay time signature of chaotic laser output, and also improve the performance in related application fields.