The resolution is an important concept in radar. Based on the mathematic model of high resolution range profile (HRRP), this paper investigates the resolution of HRRP for two ideal point targets. Theoretical analyses indicate that two ideal point targets can always be resolved in HRRP once they are separated by a distance larger than 1.7∗c/(2B), where c is the speed of light and B is the bandwidth of radar transmit signal. Whereas, two ideal point targets may be resolved in HRRP even though their separation is less than 1.7∗c/(2B). That is to say, 1.7∗c/(2B) is the sufficient and unnecessary condition of resolving two ideal point targets.