Based on the block bidding theory principles and models， the difficulties of applying block bidding theory in regionalpower markets are studied. Hydro power is scheduled first， then the paper discusses methods to classify different capacityranges of the modified load curve. Given the fact that the regional markets are divided into several price zones according toprovincial development differences， the section load constraints are introduced into the market clearing process to realize theprice zone partition automatically. Unit capacity of equal bidding price should be selected or reduced according to equalproportion step by step， with constraints of section load capacity and unit minimum output. Then the mathematical model ofblock bidding in regional power market is presented， considering the power balance， unit operation limits and section loadconstraints. This model can be solved by merit-order method combining above solutions for practical difficulties. Simulation of87-unit system shows that the presented method is effective， and block bidding application in regional power market is a goodselection for generation and grid companies.