The invention discloses a method for preparing a drug for treating pediatric esophageal achalasia. The drug is applied to the treatment of pediatric esophageal achalasia. The drug is characterized by being prepared from the following raw pharmaceutical materials in proportioning ratio by weight: fingerleaf rodgersflower rhizome, bombax malabaricum peel, paris polyphylla Sm., luffa cylindrica (L.) Roem., murraya jasminorage, poriacocos (Schw.) Wolf, citrus reticulata Blanco, rtemisia japonica Thunb., trachelospermum jasminoides (Lindl.) Lem., radix puerariae, hordeum vulgare L. and setaria italica Beauv.. The method comprises the following steps of: (1) extracting volatile oil from coarse powder of radix puerariae, bombax malabaricum peel and rtemisia japonica Thunb. for later use; (2) crushing setaria italica (L.) Beauv. into fine powder for later use; (3) carrying out water extraction and alcohol precipitation on fingerleaf rodgersflower rhizome, poriacocos (Schw.) Wolf, citrus reticulata Blanco, trachelospermum jasminoides (Lindl.) Lem., luffa cylindrica (L.) Roem., paris polyphylla Sm., murraya jasminorage and hordeum vulgare L., and drying so as to obtain a preliminary material; and (4) spraying the volatile oil into the preliminary material, adding the fine powder of setaria italica (L.) Beauv., uniformly mixing, sieving by using a 60-mesh sieve, and encapsulating. Proved by clinical trials, the drug prepared by the method has the characteristics of good treatment effect and high safety in the treatment of pediatric esophageal achalasia, so that the method is worthy of clinical application and popularization.