The variability and intermittency of DG（ Distributed Generation） outputs result in the uncertainty of gridconnected harmonic current

and thus lead to the uncertainty of harmonic distribution in distribution network with DGs. To deal with the uncertainties of DGs as harmonic sources in harmonic power flow calculation

the complex affine is adopted to replace the point value

and a complex affine output-impedance model of grid-connected inverter of DGs is built

which reflects the influence of the uncertainty of DC-bus voltage source on the harmonic current of gridconnected DGs. Based on the proposed model

the traditional deterministic harmonic power flow method is improved

and an uncertain harmonic power flow calculation method for distribution network with multiple DGs is proposed to analyze the influence of the uncertainties of DGs on harmonic current. A typical 33-bus distribution network is used for simulation

and the comparison with the calculative results of deterministic analysis method verifies the effectiveness and practical value of the proposed method.