Based on the existing algorithms of vehicle reference speeds for ABS, an improved self-adaptive algorithm was investigated. This algorithm distinguished every control cycle exactly according to the information of wheel speeds and pressure control states. The vehicle deceleration was estimated at the end of each control cycle, and the reference speeds during the next cycle were determined according to the estimated value of deceleration. The codes of this self-adaptive algorithm was written and tested as part of the self-developed ECU of ABS through road tests. Test results show that this algorithm of reference speed is valid and can meet the demands of ABS control.