Different age group of Male Kazak sheep and Xinjiang fine wool sheep were used in the current study to investigate the developmental changes of GHSR mRNA expression. After measurement of body weight, hypothalamus and pituitary were sampled to extract total RNA for determining the abundance of GHSR mRNA by RT-PCR and real-time PCR. The results indicated that: (1) For both breeds, body weight among different ages was significantly different (P<0.05), and from day 30 to 90, the Kazak’s was notable higher than the Xinjiang’s (P<0.01); (2) Hypothalamus GHSR mRNAs expression level increased firstly and then declined with growing in both breeds. From day 60 to 90, the mRNAs expression level of the Kazak was extremely higher than that of the Xinjiang (P<0.01); (3) Pituitary GHSR mRNAs expression level increased with growing in both breeds, and was highly positively correlated with the cumulative growth curves. From day 2 to 90, the pituitary GHSR expression level of the Kazak was extremely higher than that of the Xinjiang (P<0.01). The results predicated that it may be pituitary GHSR but not hypothalamus GHSR through which ghrelin influenced sheep growing.