In photovoltaic array state estimation, the dimensionality of indicator selected is narrow and will lead to big error in the judgment of abnormal state and reason, therefore, this paper proposes one kind of state evaluation method for PV arrays based on the vertical and horizontal dimensions. The method divides the characteristics parameters of PV array in accordance with hierarchy structure and defines time sequence nodes and monitoring points of PV array. From the horizontal angle, it constructs evaluation model of running status of PV array based on the evaluation scheme of positive and negative ideal point, and then obtains the best distance degrees of an indicator in different PV array unit. Afterwards, it uses the Gauss curve fitting to structure the function relations of time between the best distance degrees and evaluation index from the vertical angle, and then acquires the group of running state curve of PV arrays. Thereby, it effectively identifies the abnormal array and relevant indicators, gives warning timely, and provides decision basis for operation and maintenance of PV array. It verifies the assessment method combined with solar data of practical engineering, experimental results show that the method can accurately reflect the actual running condition of PV array, and has a certain application value.