Purpose:. Reseasch clinical charactaristic congenital ptosis and analyse some factors. Objective and Methods: cross-study non randomized clinical trial in national institute of Ophthalmology from 1/2012 to 6/2012. Result: 86 patients with 116 eyes, average is 8.52. Male consist of 61.9 percent. 76.2 percent patients were discorved under 1 year old. 38 percent suffered in both eyes and no diffrence between two eye including 11.2 percent slight, 21.6 percent average and 67.2 percent severe. 61.2 percent of these eyes has bad levator muscle function and 68,1 percent with reduced acuity vision. Ptosis without orther abnormalies consist of 9.5 percent. There are the relationship between the ptosis degree and the levator fuction.There are the differrence of percentage corneal astigmatism between each group. Anisometropia in unilateral ptosis is higher than the other. Amblyopia and astigmatism are common in the severe ptosis group. Refrative error and amblyopia always happens in ptosis. Conclusion: average is 8,52. Male consist of 61,9 percent. 76,2 percent patients were discorved under 1 year old. 38 percent suffered in both eyes including 32.8 percent slight and average. 61.2 percent of these eyes has bad levator muscle function and 68.1 percent with reduced acuity vision. There are the relationship between the ptosis degree and the levator fuction, refrative error and amblyopia.