Abstract: This study was conducted to investigate the endocrine regulatory mechanisms of follicular development in the lay-incubation cycle of Magang geese. Experiment 1: investigated the changes in palsma concentrations of PRL, LH, P4, and INB during the cycle, and the follicular development at incubation (d0), end of incubation (d10), onset of lay (d25), peak of lay (d40), end of lay (d55) and incubation (d70) in the layincubation cycle. Experiment 2, after being deprived of laying nest to terminate incubation behaviour on day 1 (d1), Magang geese were immunized intramuscularly on days 1, 23 and 45, with 1 mL of immunogen containing 1, 0.8, and 0.5 mg, respectively, of recombinant chicken PRL protein. The photoperiod under which the geese were kept was increased from 11L:13D to 16L:8D on day 33. In expreiment 1, with the termination of incubation, PRL concentration in plasma decreased, whereas the concentrations of LH, P4 and INB increased. PRL concentrations fell to lowest levels prior to the onset of lay and rose to high levels during laying to the peak when incubation initiated. LH concentration in plasma exhibited a bi-phasic pattern in the whole cycle. The patterns of P4 and INB concentrations were opposite to that of PRL, reaching to high levels at peak lay and to the lowest at incubation. Laying resumed on day 24 in the layincubation cycle, and approximately 10 follicles were recruited into hierarchical development before onset of lay, among which 8 developed to ovulation and were laid as eggs. Ninety percent of the geese exhibited incubation behabviour after laying one clutch of approximately eight eggs in approximately 30 days. Results of experiment 2 showed that immunization against PRL increased the clutch size by one egg (8.0 vs 7.0）, although initially retarded the rise of laying rate (P<0.05). Development of incubation behaviour was also delayed by one week in the PRL immunized geese, which still reached to 100% as in the control geese. Results of the two experiments indicated that the alternative secretions of PRL and LH coordinated the lay incubation cycle in Magang geese. As the results of follicular development, secretions of INB and P4, the latter through PRL secretion, determine the quota of follicular development and clutch egg size. PRL triggers the incubation behaviour and atresia of eggs at bottom on developing hierarchy, however, PRL may stimulate follicular development and egg laying around the onset of lay.