Strabismus is a type of disease in which the visual axis is skewed. It seriously affects the visual function of both eyes and can cause amblyopia and diplopia, and has a serious impact on the patient’s psychology and appearance. Treatment of strabismus includes non-surgical treatment (i.e., optical treatment, medication, etc.) and surgical treatment of strabismus. The indications and methods of surgical treatment vary for each type of strabismus. The surgeon’s plan for strabismus surgery is based not only on the patient’s type of strabismus and quantitative strabismus examination results, i.e., the degree of strabismus, but also on the patient’s eye movement, refractive status, the patient’s preoperative visual function status of both eyes, and even the patient’s age, occupation, and psychological factors. Therefore, the surgical treatment of strabismus is an “individualized treatment”. The optimal timing of surgical treatment differs for each type of strabismus. The state of eye position control in patients with intermittent exotropia is an important indicator for conservative observation or surgery. It is generally accepted that surgery is required if the strabismus is >20 PD, if the frequency of eye position deviation is >50% in the awake state, and if the masking examination reveals poor control of the orthotropia. The timing of surgical treatment for congenital internal strabismus is a focal issue, but there is a consensus that “early surgical treatment is necessary to obtain some binocular vision”. The Early vs. Late Infantile Strabismus Surgery Study (ELISS) showed that 13.5% of children with congenital internal strabismus who were treated surgically between 6 and 24 months after birth achieved coarse stereo vision at 6 years of age, compared to 3.9% of patients treated after 2 years of age, but the likelihood of reoperation was higher in children who were operated early. In paralytic strabismus, which causes significant anterior strabismus and abnormal visual function in both eyes, especially in children with a combination of abnormal head position, early surgery is required when the eye position is stable. Because of the complexity of paralytic strabismus, vertical strabismus is often combined with horizontal strabismus, or ocular motility disorders are evident, and some patients have insidious conditions that require secondary or multiple surgeries. Nevertheless, the general principles of surgical treatment for all types of strabismus are the same: to modify or restore the oculomotor and perceptual pathology, to preserve or establish the patient’s binocular visual function, especially the binocular monocular function in the original in-position and reading field, and to eliminate or improve strabismus and abnormal head position. Children with developing binocular vision and all types of strabismus that result in damage to binocular visual function require early treatment.