With the increasing penetration of distributed PV generation, its influence on harmonic of distribution network is becoming more and more serious. The optimal configuration of harmonic monitoring program is studied, and a multi node distributed photovoltaic allocation method is proposed to minimize harmonic contents of harmonic monitoring points, which reduces the influence of distributed PV on the harmonic of distribution network. First, the Monitor Reach Area (MRA) is defined according to the result whether the monitor point can observe harmonics generated by the single DG node when its capacity get to the penetration limit. Then the optimal monitor point configuration is calculated with the purpose of getting the less monitor point number and the larger MRAs. At last, a distributed PV configuration scheme is proposed using particle swarm optimization algorithm to reduce the PV harmonic and get the maximum PV penetration in the system. The performance of the scheme is illustrated in a distribution network in Shanghai, and the result implies the effectiveness of the method proposed. This work is supported by National Basic Research Program of China (973 Program) (No. 2014CB23903).