At present，high accuracy clock schemes are all designed by using the oven control crystal oscillator（OCXO）.This paper describes a new design scheme for high accuracy clock module using the temperature compensated crystal oscillator（TCXO）.In order to reduce the frequency error of oscillators，the frequency is measured by outer pulse per second（PPS）and is used to calculate the temperature coefficient of TCXO.Then the coefficient with temperature and frequency is used to produce inner PPS and the clock.The difference between inner and outer PPS is also used in calculating the temperature coefficient.The scheme has improved the precision of the inner PPS and reduced the error of the clock in giving the wrong time.The error source of this clock scheme is analyzed at length with an example given to show its application in practice.