Distributed generators（DGs） are expected to play an important role in the future power supply.The appropriate planning of DGs would potentially benefit network operators by reducing power loss and deferring or delaying the necessity for network upgrading and expansion. At present， the cost or benefit of DGs to the network operators is not properly reflected by the major distribution network charging model. The objective of this paper is to extend a well established economic pricing model， i.e.， investment cost related pricing based on DC power flow（ICRP-DC） model， to distribution network. This model has been successfully used by the UK's transmission networks. According to the characteristics of distribution network， the investment cost related pricing based on AC power flow（ICRP-AC） model is proposed. The proposed model is adapted to the distribution network investment pricing， and can consider the effects of injected/absorbed nodal active power and reactive power as well. Compared with other models， the proposed model can provide the relevant economic signals to appropriate locations of DGs. The simulation results validate the effectiveness of the presented model， and the comparison analysis with ICRP-DC model is carried out.