This disclosure discloses a method and apparatus for transmitting data in a robot operating system. The robot operating system includes a transmitting node, a receiving node, and a shared memory as a transmission medium between the transmitting and receiving nodes. The method in a particular embodiment includes: traversing, by the transmitting node, a sequence of data templates stored in advance in the shared memory, and determining whether the respective data templates in the sequence of data templates are currently being written into or read from; identifying a data template in the sequence of data templates currently being neither written into nor read from as a target data template, and obtaining information of the target data template; and writing data into the target data template according to the information of the target data template. This embodiment can improve the performance of transmitting the data while occupying less memory resources.