For pediatric flexible flatfoot, the subtalar extra-articular screw arthroereisis (SESA) and endosinotarsal device are the most popular techniques in current practice. Nevertheless, scarce literature is available comparing the outcomes between these two techniques. Thus, we aimed to provide a meta-analysis for the radiographic and clinical outcomes, respectively. A systemic search for correction of pediatric flexible flatfoot using subtalar arthroereisis was conducted mainly in Pubmed and Scopus, and the search was completed on 31 Dec., 2019. The standardized mean differences (SMD) of postoperative versus preoperative calcaneal pitch and Meary's angle were defined as the primary outcomes, whereas the preoperative versus posteoperative AOFAS (American Orthopaedic Foot and Ankle Society) as the secondary outcome. The meta-analysis included 12 comparative studies comprising 2063 feet in total. The quantitative analysis showed a marked improvement in Meary's angle of endosinotarsal cone implant group (SMD: 4.298; 95% CI 2.706-5.889) than exosinotarsal screw group (SMD: 1.264; 95% CI 0.650-1.877). But no significant difference was noted between both groups in calcaneal pitch and AOFAS. The exosinotarsal screw and endosinotarsal device are both effective arthroereisis implant for pediatric flexible flatfoot. While considering the correction of Meary's angle, the endosinotarsal device is better than exosinotarsal screw.