A cloud-based electronic prescription transmission method comprising the steps of: requesting an electronic prescription from a hospital server, when a cloud server receives a request for the electronic prescription from a user terminal, by the cloud server; extracting patient information and prescription information stored in an EMR DB, by the hospital server; converting the prescription information according to a unique API, by an API builder unit which is included in the hospital server; authenticating the converted prescription information through an electronic signature of the clinic, encrypting the converted prescription information, and transmitting the electronic prescription to the cloud server, by the hospital server, creating a QR code, and temporarily storing the electronic prescription when a drugstore is selected by the user terminal, by the cloud server; transmitting at least one among the QR code, the electronic prescription, and drugstore information on the selected drugstore to a drugstore server, by the cloud server, confirming the electronic prescription, by the drugstore server, and storing the electronic prescription by the drugstore server, deleting the temporarily stored electronic prescription from the cloud server when reception of medicine is informed from the user terminal, wherein at the step of converting the prescription information by the API builder unit, the API builder unit converts the prescription information by creating a data source, conveniently creating an SQL query through an SQL query creation guide, converting the data source into a standard data through an API builder, and repeatedly verifying the data. requesting an electronic prescription from a hospital server, when a cloud server receives a request for the electronic prescription from a user terminal, by the cloud server; extracting patient information and prescription information stored in an EMR DB, by the hospital server; converting the prescription information according to a unique API, by an API builder unit which is included in the hospital server; authenticating the converted prescription information through an electronic signature of the clinic, encrypting the converted prescription information, and transmitting the electronic prescription to the cloud server, by the hospital server, creating a QR code, and temporarily storing the electronic prescription when a drugstore is selected by the user terminal, by the cloud server; transmitting at least one among the QR code, the electronic prescription, and drugstore information on the selected drugstore to a drugstore server, by the cloud server, confirming the electronic prescription, by the drugstore server, and storing the electronic prescription by the drugstore server, deleting the temporarily stored electronic prescription from the cloud server when reception of medicine is informed from the user terminal, wherein at the step of converting the prescription information by the API builder unit, the API builder unit converts the prescription information by creating a data source, conveniently creating an SQL query through an SQL query creation guide, converting the data source into a standard data through an API builder, and repeatedly verifying the data.