The invention discloses a transmission-distribution-integrated optimization scheduling method with consideration of multi-distribution-network access. The method comprises: a sub transmission network optimization model based on a supply curve is established, and a transmission network supply curve SCtran after correction with consideration of network losses is obtained by using the sub transmission network optimization model; a multi-distribution-network sub optimization model based on a demand curve is established and demand curves SCdis of all distribution networks are obtained by using the multi-distribution-network sub optimization model; and a transmission-distribution-integrated optimization scheduling algorithm model with consideration of multi-distribution-network access is established, mutual optimization iteration between the transmission and distribution networks is carried out by combining the supply curve obtained by the sub transmission network optimization model and the demand curves obtained by the multi-distribution-network sub optimization model so as to obtain a transmission-distribution-integrated optimized-scheduling global optimization result. According to the invention, optimized configuration of the whole system resources is carried out, so that the system cost is reduced, the resource availability rate is increased, and the system operation safety is improved.