The invention belongs to the technical field of ultra wide band wireless communication electronics and particularly relates to an all-digital under-sampling pulse ultra wide band receiver. The system architecture comprises an off-chip band pass filter, a low noise amplifier, a variable gain amplifier, an on-chip band pass filter, an analog to digital converter, a back-end digital processing module, a power detector and a controller; the analog to digital converter directly quantizes amplifying signals at the front end of radio frequency in an under-sampling manner; and the digital processing module firstly carries out channel estimation, then realizes sign synchronization and generates a channel template by utilizing the channel estimation result and finally detects output data by utilizing the channel template. The all-digital under-sampling pulse ultra wide band receiver can solve the defects of poor flexibility, low performance, slow data transmission rate, high bit error rate, large power consumption and the like of some existing all-digital structure receivers, has the advantages of fast data transmission rate of hundreds of megabytes, low power consumption and high reliability and can be applied to short-distance wireless communication fields which have high-speed data transmission, such as multimedia, wireless local networks and the like.