In order to maximize the flexible regulation potential of load resources, this paper studies the participation of data centers in day-ahead electricity market. Through the optimized scheduling model of the data center cluster based on the spatio-temporal adjustable characteristics of the load, its adjustable potential for participating in demand response is obtained and the response contract is designed accordingly. From the perspective of demand-side resources participating in market bidding, a quotation optimization model for load aggregators considering load curtailment, load shifting, onsite generation and energy storage is established to obtain a market bidding strategy. The effectiveness and superiority of this model are verified through numerical experiments.