Recently, a distance measurement radar system has been widely used for automobile collision avoidance. Though the distance detection radar commonly proposed is frequency modulated continuous wave (FMCW) radar, the need for a relatively high bandwidth and high frequency linearity will increase the complexity of the system design. In this paper, a pseudo-random noise (PRN) sequence radar for automobile collision distance measurement is discussed. This system is designed at the center frequency of 24 GHz. Due to the low correlation of the different PRN code sequences, it can be used in a noisy environment which contains other PRN signals with less interference. The experimental results show that a PRN radar has high anti-interference property in the noisy environment.