In order to study the influence of DC power grid structure changes on power flow transfer and explore how to design a DC grid with better power transfer characteristics, the DC distribution coefficient is used to quickly calculate the power flow increment and load rate of the other lines when one line is disconnected. Power distribution entropy is used to measure the distribution of load rate of the DC grid. Power transfer entropy is used to reflect the influence of power flow transfer of the other lines in the grid. The structural eigenvalue is used to measure the DC line characteristics. A±400 kV five-terminal MMC-MTDC system is established in PSCAD/EMTDC, and simulation results show that power distribution entropy of the grid decreases with the increase of the structural eigenvalue; The power transfer entropy of the line connecting to the power supply and the load is relatively high. After adding a line connecting to the power supply and the load, the power transfer entropy of the DC line in the grid generally has different degrees of reduction. It is concluded that in the design of the DC grid structure, priority is given to erecting the DC line connecting the power supply with the load, that can effectively reduce the power distribution entropy of the DC grid and the power transfer entropy of the DC line. So that the DC grid has better power flow transfer characteristics.