The present disclosure provides an operation adjustment method and system for metro trains in a delay scenario. The method includes: acquiring basic parameters, current delay information and current online train information in a metro system; determining a detaining position of a departing train and an operation strategy of a waiting train according to the acquired; determining a next state of a running train according to the detaining position, the operation strategy, and the acquired; and optimally configuring an available rolling stock resource of the metro system according to the next state of the running train and operation data. The present disclosure can automatically adjust the operation diagram according to the delay information and reasonably change the operation plan of the rolling stock, so as to reduce influences of the delay on passengers and improve the actual fulfillment rate of the operation diagram.