Objective To explore the effect of combined fascia sheath (CFS) suspension surgery on palpebral ffssure height (PFH) and margin reffex distance 1 (MRD1) in patients with severe ptosis. Methods A total of 40 patients (42 eyes) with severe ptosis admitted to the Department of Plastic Surgery, Wuhan Third Hospital from January 2021 to December 2024 were selected. They were divided into the extremely poor muscle strength group (≤2 mm) and the fair muscle strength group (3-4 mm) according to the preoperative levator palpebrae superioris muscle strength, with 20 patients (21 eyes) in each group. Both groups were treated with CFS suspension. The PFH, MRD1, complication rate and satisfaction were compared between the two groups. Results The PFH and MRD1 in the fair muscle strength group at 6 months after operation were higher than those in the extremely poor muscle strength group (P<0.05). There were no statistically signiffcant differences in the incidence of transient diplopia, conjunctival prolapse, eyelid incompletely closed and overall complications between the two groups (P>0.05). There was no statistically signiffcant difference in satisfaction rate between the two groups (P>0.05). Conclusion CFS suspension surgery yields high satisfaction and low complication rate in the treatment of severe ptosis with different muscle strength levels. However, patients with fair levator palpebrae superioris muscle strength have more advantages in postoperative PFH and MRD1 improvement.