The present invention discloses a precise time measuring method and a measuring circuit. The procedure is as follows: {1} an outside reference 1PPS pulse signal, an event signal to be measured and a 10 MHz standard signal are input, the first edge of a reference clock after the rising edge of the reference 1PPS pulse is extracted as a measuring pulse A and the first edge of the reference clock after the rising edge of the event signal to be measured is extracted as a measuring pulse B; {2} the interval between the measuring pulses A and B is computed out as the outlier time T 0 of the event tobe measured; {3} the interval T 1 between the measuring pulse A and the 10 MHz standard signal, and the interval T 2 between the measuring pulse B and the 10 MHz standard signal are obtained throughthe tapped delay line method; {4} the precise time t e is obtained from the formula t e = t 1PPS + T 0 +T 1 -T 2, of which t 1PPS is the time code of the reference 1PPS. The tapped delay line technology of the present invention can output a primary time and frequency standard and can measure the event occurrence time precisely of multi nodes under a unified primary time and frequency standard.