Abstract: In this experiment, the method of embryonic tissue culture and the biochemical method have been used to determine the activity of AKP in the tissue culture fluid which is from 97 duck embryos, aged 13 days, belonging to 4 families; and the productive traits of the half-sib female ducks have also been recorded and studied.The results show: the active intensity of AKP in the duck embryo tissue culture fluid is negatively correlated with the days of sex-maturity of the half-sib female ducks(r=-0.713), but it is positively correlated with the laying number of the ducks aged 240 and 300 days.The correlation coefficients are 0.866 and 0.940 respectively. When the activity of AKP in the duck embryo tissue culture fluid is at 4-7 King units, the sex-maturity of the half-nib female ducks is at the age of 137-143 days, while at 8-12 King units, the sex-maturity is at the age of 121-126 days, 16-17 days earlier than the former. The different is significant(p0.05). As the active intensity rises, the laying number of its half-nib female ducks aged 240 and 300 increases; the difference among the families are highly significant(p0.01).Therefore, according to the activity of AKP in duck embryo tissue culture fluid, we evaluate the stud egg-laying ducks among different families in the early stage. It can be over half a year earlier than if the traditional method is adopted.