The invention discloses an intelligent monitoring and operation and maintenance system for a transformer, and relates to the technical field of informatization system integration, and the system comprises a sensing unit which is used for obtaining all operation data and indexes of the transformer; a data acquisition terminal which is used for receiving the data acquired by the sensing unit and processing the data to obtain pre-processed data; a transformer cloud platform which receives the pre-processed data of the data acquisition terminal, stores, analyzes, counts and learns the pre-processed data, and performs safety protection on the pre-processed data; and a transformer full-life standard operation intelligent terminal which is used for interacting with transformer users, maintenance management personnel, design, production and manufacture personnel and management personnel, and querying, maintaining, predicting and replacing transformer equipment. Through a data acquisition function, a standard operation management function and a task management function on the mobile terminal, data are uploaded to the cloud platform in real time, the data are analyzed, diagnosed and predicted, and a maintenance and repair scheme is provided.