Objective To investigate the eyelid and orbital development of congenital microphthalmia. Design Prospective case se- ties. Participants 23 eyes of 23 patients with congenital microphthalmia aged from 6 months to 78 months. Methods The parameters of palpebral fissure length (PFL), palpebral fissure height(PFH) were measured in all patients. Also, combining the computer tomography (CT) imaging with the computer-aided design system, the anteroposterior axis of eyeball and orbital volumn were calculated automatically. To e- valuate the influence factor of eyelid and orbital growth, correlations between age, anteroposterior axis of eyeball and PFL, PFH, orbital volumn were analyzed. Main Outcome Measures PFL, PFH, anteroposterior axis of eyeball and orbital volumn. Results The PFL, PFH, anteroposterior axis of eyeball and orbital volumn in micro-side were (16.44?3.24) mm, (2.47?1.48) mm, (11.99?3.33) mm, (14.19?2.37) ml respectively. These parameters above were all significantly smaller than the unaffected side (all P=0.000). Moreover, orbital volume showed a strong linear correlation with the anteroposterior axis of eyeball and age(r=0.62, 0.63;p=0.037, 0.035). Both PFL and PFH were corelated with the anteroposterior axis of eyeball (r=0.54, 0.53; P=0.030,0.034), while showing no significant difference with age. According to the an- teroposterior axis of eyeball, two groups, including group less than or equal to 12 mm (10 cases) and group more than 12 mm (13cases), whose PFL,PFH and orbital volumn were (13.50?1.97) mm, (1.08?0.66) mm; (12.73?0.95) ml, (18.20?2.49) mm; (3.30?1.16) mm, (15.05?2.57) ml, respectively. They had statistically significant difference in PFL, PFH and orbital volumn (P=0.001, 0.003,0.024). Conclusion The development of eyelid and orbit with congenital microphthalmia is obviously retarded. The smaller the eyeball is, the much worse in- fluence in eyelid and orbital growth is. The intervention therapy in early stage as far as possible is fundamental approach in simulating the eyelid and orbital development, or preventing and reducing the incidence of orbital deformity.