Ultra wideband UWB radars in the 24 GHz domain are currently under development for many automotive applications. Automotive UWB radar is attractive for application in short range automotive radar systems using 22 to 29GHz in order to improve road safety and realize intelligent transportation. By employing a direct conversion receiver, automotive UWB radar is able to meet size and cost reduction requirements. Direct conversion architecture poses a dc-offset problem, which corrupts velocity ambiguity in automotive UWB radar. In this paper, we proposed a mean-padding method to reduce zero-padding FFT error due to dc-offset in automotive UWB radar using direct conversion receiver. Zero-padding degrades vehicular velocity measurement probability. The results of computer simulation and experimentation using the designed RF module of the automotive UWB radar show that the presented method achieves a better velocity measurement probability.