Abstract: 160 Langshan breeder hens were randomly divided into 3 groups, fed with 10% (low), 15% (control) and 20% (high) crude protein (CP) diet, respectively for21days. Fertile eggs were collected 10 days after the dietary treatment. 10 eggs each group were used to determine the yolk deposition of maternal thyroid hormones and glucagon with radioimmunoassay, and the remaining eggs were incubated. Newly hatched chickens were raised under the same condition until 28 days of age and the growth performance of the offspring was recorded. 10 chicks from each group were sacrificed on day 1 and day 28, respectively for sampling. Results: Dietary protein level showed no significant effect on body weight of the hens, yet the egg laying rate and egg weight decreased markedly in the low-CP diet group (p<0.05). Egg weight in the high-CP diet group is significantly higher than the controls. Yolk contents of T3 and glucagon didn’t show differences among groups, while that of T4 in the high-CP diet group was significantly higher than the other two groups (p<0.05). At hatching, serum levels of T3 in the low-CP group and T4 in the high-CP diet group were significantly higher than the controls (p<0.05). Strong positive relationship was found between hatch weight and fertile egg weight (R2=0.9275, p<0.01). Both high- and low- CP diet group showed higher growth rate after hatching. Relative breast muscle weight and body weight in the low-CP diet group were markedly higher than that in the control group on 28 days (p<0.05), whereas that in the high-CP group showed a trend of increase, compared with that of the control group (p=0.08). Conclusion: Dietary protein level in hens could significantly change the yolk deposition of maternal hormones and offspring growth.