This discolor discloses a method and apparatus for monitoring a message transmission frequency in a robot operating system. A specific implementation of the method includes: writing to-be-transmitted messages, into a pre-allocated memory; obtaining time points when the to-be-transmitted messages are written into the memory, and recording the time points in a preset time point list; determining a message transmission frequency within a preset time interval based on the time points in the time point list; and comparing the message transmission frequency with a preset message transmission frequency threshold, and generating monitoring information based on a comparing result. This implementation monitors the message transmission frequency of a process to thereby avoid information codes related to monitoring of each application from being added to the application so as to reduce the program debugging cost, and improve the monitoring efficiency.