The invention discloses an iron and steel enterprise surplus gas optimization scheduling method based on peak-valley time-of-use power price. According to the method, self-generating power of the peak period is increased by utilizing difference of the peak-valley time-of-use power price. The system according to the method is composed of four parts of a gas pipe network state identification module, a peak-valley power price calculation module, a gas tank optimization operation guidance module and an optimization benefit evaluation module. The gas pipe network state identification module analyzes and judges whether the gas system is in the surplus state in real time and generates an optimization enabling signal. The peak-valley power price calculation module is responsible for calculating the power price of the current moment and a certain moment in the future. The gas tank optimization operation guidance module is responsible for calculating the target tank position of the gas tank and the expected tank position of the current moment. The optimization benefit evaluation module is responsible for performing statistics of economic benefit brought by gas tank optimization operation. The method is easy and convenient to operate and easy to implement so that production cost of iron and steel enterprises can be reduced by changing the proportion of self-generating power of the peak-valley periods without increasing generating power.