The invention provides a method for calculating the three-phase load flow of an active power distribution network based on a node voltage. The method comprises the steps of taking the real part and the imaginary part of the phase voltage of a node as state variables, selecting the real part and the imaginary part of each phase of injection current of the node as known variables, establishing a relation between the known variables and unknown variables by use of a node voltage equation, and directly calculating a factor table through a formula. The method for calculating the three-phase load flow of the active power distribution network based on the node voltage is capable of processing multiple PV nodes and links and is not limited by the number of the links; the factor table of a jacobian matrix is directly calculated through the formula, and factorization is avoided during calculation so that the calculation amount can be greatly reduced; the jacobian matrix is highly sparse and thus convenient for storage and calculation; in each iteration, the three phases are completely decoupled; the calculation result is capable of guaranteeing that zero injection constraint is strictly satisfied.